The Paleo Diet

What is Paleo Diet

A paleo diet is a dietary plan based on foods similar to what might have been eaten during the Paleolithic era, which dates from approximately 2.5 million to 10,000 years ago. Other names for a paleo diet include Paleolithic diet, Stone Age diet, hunter-gatherer diet and Caveman Diet ¹. This diet consists of foods that are assumed to have been available to humans prior to the establishment of agriculture. The Paleolithic period began approximately 2.5 million years ago, when humans first started to use stone tools. The period ended with the emergence of agriculture approximately 10,000 years ago. The paleo diet is currently one of the most fashionable diets in the world.

The principal components of this diet are wild-animal source and uncultivated-plant source foods, such as lean meat, fish, vegetables, fruits, roots, eggs, and nuts. The diet excludes grains, legumes, dairy products, salt, refined sugar, and processed oils, all of which were unavailable before humans began cultivating plants and domesticating animals. The main ingredient lacking in a Paleolithic diet is calcium, which must be supplemented to prevent bone mineral loss ¹.

The appeal of this diet is that, since the advent of agriculture and animal domestication approximately 10,000 years ago, there has been little time for significant evolution of core metabolic and physiological processes in response to the major dietary changes introduced by these new food-producing practices. Proponents of the Paleolithic diet believe that modern humans are genetically adapted to a Paleolithic diet and not to the current so-called civilized diet. They believe that the modern so-called civilized diet may lead to chronic diseases such as Type 2 Diabetes Mellitus, obesity, and cardiovascular disease, which are associated with societal affluence ².

Potential disadvantages of a Paleolithic diet might include deficient intake of vitamin D and calcium as well as exposure to environmental toxins from high intake of fish ³.

Furthermore, there is evidence of an association between consumption of red meat (though possibly not of white meat such as chicken) and an increased risk of developing colorectal cancer ⁴, though the evidence is probably confounded by factors like the type of red meat (eg. beef versus pork) ⁵, ⁶ and the way the meat is cooked ⁷, ⁸. The National Cancer Institute’s Division of Cancer Epidemiology & Genetics research has identified that red and processed meats are associated with an increased risk of several cancers, while poultry and fish intake may be protective. Investigators are currently studying carcinogenic compounds formed in meat during processing or cooking, such as: Heterocyclic amines, N-nitroso compounds and Polycyclic aromatic hydrocarbons ⁵, ⁷. Subjects on a paleo diet should however benefit from not consuming processed meat since the evidence that processed meat increases the risk for colorectal cancer is stronger.

The Paleo Diet is based on eating lots of lean meats, fresh fruits, and vegetables.

The Paleo Diet is the one and only diet that ideally fits our genetic makeup. Just 333 generations ago—and for 2.5 million years before that—every human being on Earth ate this way. It is the diet to which all of us are ideally suited and the lifetime nutritional plan that will normalize your weight and improve your health. We didn’t design this diet—Nature did. This diet has been built into our genes.

What do Paleolithic people have to do with us ? Actually, quite a lot: DNA evidence shows that basic human physiology has changed little in 40,000 years. Literally, we are Stone Agers living in the Technology and Space Age; our dietary needs are the same as theirs. Our genes are well adapted to a world in which all the food eaten daily had to be hunted, fished, or gathered from the natural environment—a world that no longer exists. Nature determined what our bodies needed thousands of years before civilization developed, before people started farming and raising domesticated livestock.

The aim of a paleo diet is to return to a way of eating that’s more like what early humans ate. The belief is that the human body is better suited to that type of diet than to the modern diet that emerged with farming. A paleo diet typically includes lean meats, fish, fruits, vegetables, nuts and seeds — foods that in the past could be obtained by hunting and gathering. A paleo diet limits foods that became common when farming emerged about 10,000 years ago. These foods include dairy products, legumes and grains.

Many of our health problems today are the direct result of what we EAT and do not do. This section will show you where we went wrong—how the Standard American Diet (SAD) wreak havoc with our Paleolithic (Old Stone Age) constitutions. It will also show you how you can lose weight and regain health and well-being by eating the way our hunter-gatherer ancestors ate—the diet that nature intended.

This loss of humanity’s original way of life matters a great deal. Why ? Look at us. We’re a mess. We eat too much, we eat the wrong foods, and we’re fat. Incredibly, more Americans are overweight than aren’t: 68 percent of all American men over age twenty-five, and 64 percent of women over age twenty-five are either overweight or obese. And it’s killing us. The leading cause of death in the United States—responsible for 35 percent of all deaths or 1 of every 2.8 deaths—is heart and blood vessel disease. Seventy-three million Americans have high blood pressure; 34 million have high cholesterol levels, and 17 million have type 2 diabetes. It’s not a pretty picture.

Farming changed what people ate and established dairy, grains and legumes as additional staples in the human diet. This relatively late and rapid change in diet, according to the hypothesis, outpaced the body’s ability to adapt. This mismatch is believed to be a contributing factor to the prevalence of obesity, diabetes and heart disease today.

Clinical Research

There is little clinical research on the benefits of paleo diets. A few clinical trials lasting 12 weeks or less have been conducted with small groups of participants.

These trials suggest that a paleo diet may provide some moderate benefits when compared with diets of fruits, vegetables, lean meats, whole grains, legumes and low-fat dairy products. These moderate benefits may include:

• More weight loss,
• Improved glucose tolerance,
• Better blood pressure control,
• Better appetite management

However, longer trials with large groups of people randomly assigned to different diets are needed to understand the long-term, overall health benefits and possible risks of a paleo diet.

The Benefits of Paleo Diet on Type 2 Diabetes and on Cardiovascular risk factors in Type 2 Diabetes

Type 2 diabetes is characterised by fasting hyperglycaemia as a result of insulin resistance and defects in insulin secretion. Obesity is the major risk factor for the development of the condition and a number of studies — including the Diabetes Prevention Program, the Da Qing IGT and Diabetes Study, and the Finnish Diabetes Prevention Study — have shown that lifestyle modification (diet and exercise) can significantly prevent the progression of glucose intolerance (prediabetes) to diabetes by up to 58% ⁹, ¹⁰, ¹¹. In addition, a recent study showed that a very-low-calorie diet for 8 weeks resulted in remission of type 2 diabetes for at least 6 months in 40% of the participants ¹². As such, clinical guidelines prescribe lifestyle modification as first-line treatment for type 2 diabetes and indeed throughout the management of the disease process ¹³. Therefore, it is clear that dietary intervention is a critical component of the glucose-lowering strategy in diabetes ¹⁴.

In a 2009 report by Jönsson and colleagues in Cardiovascular Diabetology ¹⁵ has highlighted the potential benefits of a Paleolithic diet for patients with type 2 diabetes. In that randomized crossover study spanning two consecutive 3-month study periods, involving 13 patients with type 2 diabetes, 3 women and 10 men, were instructed to eat a Paleolithic diet based on lean meat, fish, fruits, vegetables, root vegetables, eggs and nuts; and a Diabetes diet designed in accordance with dietary guidelines. Outcome variables included changes in weight, waist circumference, serum lipids, C-reactive protein, blood pressure, glycated haemoglobin (HbA1c), and areas under the curve for plasma glucose and plasma insulin in the 75 g oral glucose tolerance test. Dietary intake was evaluated by use of 4-day weighed food records. Study participants had on average a diabetes duration of 9 years, a mean HbA1c of 6,6% units and were usually treated with metformin alone (3 subjects) or metformin in combination with a sulfonylurea (3 subjects) or a thiazolidinedione (3 subjects).

The Paleolithic diet excluded dairy products, cereal grains, beans, refined fats, sugar, candy, soft drinks, beer, and any extra addition of salt. The following items were recommended in limited amounts for the Paleolithic diet: eggs (≤2 per day), nuts (preferentially walnuts), dried fruit, potatoes (≤1 medium-sized per day), grape seed or olive oil (≤1 tablespoon per day), and wine (≤1 glass per day). The intake of other foods was not restricted and no advice was given with regard to proportions of food categories (such as animal versus plant foods). In that study ¹⁵, the Paleolithic diet was lower in cereals, dairy products, potatoes, beans, and bakery foods but higher in fruits, vegetables, meat, and eggs compared to the diabetes diet. The Paleolithic diet worked out to be lower in total energy, energy density, carbohydrate, dietary glycemic load, fiber, saturated fatty acids, and calcium but higher in unsaturated fatty acids, dietary cholesterol, and several vitamins and minerals ¹⁵.

Compared to the diabetes diet, the Paleolithic diet (after two consecutive 3-month study periods) resulted in lower mean values of HbA1c (-0.4% units), triacylglyceride (-0.4 mmol/L), diastolic blood pressure (-4 mmHg), weight (-3 kg), BMI (-1 kg/m2) and waist circumference (-4 cm), and higher mean values of high density lipoprotein (HDL) cholesterol (+0.08 mmol/L). The Paleolithic diet was mainly lower in cereals and dairy products, and higher in fruits, vegetables, meat and eggs, as compared with the Diabetes diet. Further, the Paleolithic diet was lower in total energy, energy density, carbohydrate, dietary glycemic load, saturated fatty acids and calcium, and higher in unsaturated fatty acids, dietary cholesterol and several vitamins. Dietary Glycemic Index was slightly lower in the Paleolithic diet (GI = 50) than in the Diabetic diet (GI = 55). CONCLUSION: Over a 3-month study period, a Paleolithic diet improved glycemic control and several cardiovascular risk factors compared to a Diabetes diet in patients with type 2 diabetes mellitus ¹⁵.

The mechanism of achieving greater improvements in levels of cardiovascular risk factors with a Paleolithic diet compared to diabetes diet is not known. In the Jönsson and colleagues study, the diets of subjects during their period of consuming a Paleolithic diet (compared to a diabetic diet) contained fewer calories and a lower glycemic index in spite of a lower fiber content. The investigators postulated that a Paleolithic diet (compared to a diabetes diet) is more satiating and facilitates a reduced caloric intake. In fact, the Paleolithic diet resulted in greater reductions in both weight and waist circumference. The higher amount of fruit and vegetables during the Paleolithic period was postulated to have promoted weight loss because of the high content of water in fruit, which may be satiating. The Paleolithic diet compared to the diabetes diet resulted in a higher percentage of protein intake as a percentage of total daily calories. A weight loss diet with moderate carbohydrate, moderate protein has been shown to result in more favorable changes in body composition, dyslipidemia, and the post-prandial insulin response compared to a high-carbohydrate, low-protein diet ¹⁶. Therefore, the greater protein intake during a Paleolithic diet might confer an additional benefit (beyond weight reduction) in its favorable effects on risk reduction for metabolic disease.

Comment

What is needed now is more clinical data with greater numbers of subjects and longer study durations so that more robust conclusions can be drawn ¹.

Similarly, in nine overweight healthy individuals, a Paleolithic diet for 10 days resulted in no change in fasting plasma glucose or insulin levels, but it showed reduced plasma lipid levels and blood pressure compared with the baseline usual diet ¹⁷. It is interesting that, while insulin levels during an oral glucose tolerance test were lower with the Paleolithic diet compared with baseline, the authors did not report the glycaemic excursions during this test. Moreover, a 2-week study in obese patients with the metabolic syndrome ¹⁸ did not show an effect on glucose tolerance, but it resulted in reduced blood pressure and plasma lipid levels associated with a small but significant decrease in weight.

In patients with ischaemic heart disease plus either glucose intolerance or type 2 diabetes, a Paleolithic diet for 12 weeks resulted in reduced glucose and insulin
excursions during the glucose tolerance test and was associated with a 26% reduction in energy intake, compared with a Mediterranean-style diet ¹⁹

In addition to the above studies of patients with type 2 diabetes (and cardiovascular risk factors), in a more recent study published in the Medical Journal of Australia, August 2016, by an associate professor Sofianos Andrikopoulos, head of the Islet Biology and Metabolism Research Group at the University of Melbourne ¹⁴ showed that studies are inconclusive about the benefits of the Paleo diet in patients with type 2 diabetes. He said that in the absence of changes in weight or energy intake, the Paleolithic diet is as effective in improving the above metabolic parameters as a standard diet. However, given that even very short deficits in energy balance can improve metabolic parameters ²⁰, it is difficult to make strong conclusions about the long term benefits of the Paleolithic diet in type 2 diabetes (or any other condition), because of the short duration of the interventions (less than 12 weeks), the lack of a proper control group in some instances, and the small sample size (less than 20 individuals) of the above studies. While it makes sense that the Paleolithic diet promotes avoidance of refined and extra sugars and processed energy dense food, clearly more
randomised controlled studies with more patients and for a longer period of time are required to determine whether it has any beneficial effect over other dietary advice.

What Effect Does a Paleolithic Diet Have on Cardiovascular Risk Factors ?

The metabolic effects on humans consuming a Paleolithic diet have been studied in only a handful of studies to date. O’Dea and colleagues reported a controlled 3-month trial of a Paleolithic diet in 13 healthy northwestern Australian Aborigines in Diabetes Care in 1980. Thirteen full-blood Aborigines from the Mowanjum Community, Derby, Western Australia, cooperated in the present study. They spent 3 mo living in their traditional hunter-gatherer life-style, after which their insulin response to glucose was measured in a starch tolerance test. The findings were compared in follow-up studies conducted 3 mo after returning to their urban environment. Similar studies were conducted in Caucasians of comparable age and weight. The data suggest that these Aborigines have an abnormally high insulin response to ingested glucose, which is ameliorated, but not normalized, by reverting to their traditional life-style. Glucose levels were unaffected by the dietary intervention in these subjects without diabetes ²¹.

O’Dea reported an uncontrolled study of initiating a Paleolithic diet in a cohort of 10 northwest Australian Aboriginal type 2 diabetes patients, they were middle aged (53.9 +/- 1.8 yr) and overweight (81.9 +/- 3.4 kg) in 1984. Adoption of a hunter–gatherer lifestyle for 7 weeks resulted in a 10% weight loss (average, 8 kg) and reductions in 2 h glucose levels as well as fasting levels of glucose, insulin, and triglycerides ²². A detailed analysis of food intake over 2 wk revealed a low-energy intake (1200 kcal/person/day). Despite the high contribution of animal food to the total energy intake (64%), the diet was low in total fat (13%) due to the very low fat content of wild animals. The marked improvement in glucose was due to both a fall in fasting glucose (11.6 +/- 1.2 mM before, 6.6 +/- 0.8 mM after) and an improvement in postprandial glucose clearance (incremental area under the glucose curve: 15.0 +/- 1.2 mmol/L/h before, 11.7 +/- 1.2 mmol/L/h after). Fasting plasma insulin concentration fell (23 +/- 2 mU/L before, 12 +/- 1 mU/L after) and the insulin response to glucose improved (incremental area under the insulin curve: 61 +/- 18 mU/L/h before, 104 +/- 21 mU/L/h after). The marked fall in fasting plasma triglycerides (4.0 +/- 0.5 mM before, 1.2 +/- 0.1 mM after) was due largely to the fall in VLDL triglyceride concentration (2.31 +/- 0.31 mM before, 0.20 +/- 0.03 mM after ²².

Lindeberg and associates reported a randomized controlled study in Diabetologia in 2007 in which a cohort of 29 patients with ischemic heart disease and either glucose intolerance or type 2 diabetes was placed on either a Paleolithic diet or a Mediterranean diet. The Mediterranean diet was based on whole grains, low-fat dairy products, vegetables, fruits, fish, oils, and margarines. They found improved glucose tolerance independent of weight loss after 12 weeks in both groups, but the improvement was significantly greater in the Paleolithic diet group. There was no relationship between improvement in glucose tolerance and any decline in weight or waist circumference ²³.

Osterdahl and coworkers reported a small uncontrolled 3-week study of a Paleolithic diet in 14 healthy subjects in the European Journal of Clinical Nutrition in 2008. They found significant improvements with mean weight decreased by 2.3 kg, body mass index (BMI) by 0.8, waist circumference by 0.5 cm, systolic blood pressure by 3 mm Hg and plasminogen activator inhibitor-1 by 72%. Regarding nutrient intake, intake of energy decreased by 36%, and other effects were also observed, both favourable (fat composition, antioxidants, potassium-sodium rate) and unfavourable (calcium) ²⁴.

The effect of a Paleolithic diet on a variety of metabolic risk factors for cardiovascular disease in an uncontrolled trial was reported in August 2009 in the European Journal of Clinical Nutrition. Compared with the usual diet, nine sedentary subjects receiving the intervention diet experienced (a) significant reductions in blood pressure, (b) improved arterial distensibility, (c) significant reduction in plasma insulin versus time in the area under the curve during oral glucose tolerance testing, and (d) significant reductions in total cholesterol, low-density lipoproteins, and triglycerides. The authors concluded that even short-term consumption of a Paleolithic type diet improves blood pressure and glucose tolerance, decreases insulin secretion, increases insulin sensitivity, and improves lipid profiles without weight loss in healthy sedentary humans ²⁵.

The effect of a Paleolithic diet in a randomized controlled trial on domestic pigs was reported in 2006. Jönsson and colleagues provided either a Paleolithic diet or cereal-based swine feed to 24 pigs during a 15-month study. The pigs receiving a Paleolithic diet weighed less and had less subcutaneous fat deposits, lower C-reactive protein levels, lower blood pressure, and greater insulin sensitivity than pigs that received a cereal-based diet. The cereal-fed pigs demonstrated a low-grade inflammation of the exocrine pancreas, although no significant difference was seen in fasting glucose levels between groups ²⁶.

Paleolithic Diet and Cholesterol

Recent small study with twenty volunteers (10 male and 10 female) with high blood cholesterol (hypercholesterolemia) aged 40 to 62 years. Volunteers were not taking any cholesterol-lowering medications and adhered to a traditional heart-healthy diet for 4 months, followed by a Paleolithic diet for 4 months. Four months of Paleolithic nutrition significantly lowered mean total cholesterol, LDL cholesterol, and triglycerides (TG) and increased HDL cholesterol, independent of changes in body weight, relative to both baseline and the traditional heart-healthy diet. Paleolithic nutrition offers promising potential for nutritional management of hyperlipidemia in adults whose lipid profiles have not improved after following more traditional heart-healthy dietary recommendations ²⁷.

Paleo Diet Could Cause Rapid Weight Gain

The study by Melbourne University researchers, who set out to prove the benefits of the Paleo diet have instead discovered it could cause significant and rapid weight gain in laboratory mice ²⁸. The objective of the study was to assess whether a low-carbohydrate and therefore high-fat diet (LCHFD) is beneficial for improving the endogenous insulin secretory response to glucose in prediabetic New Zealand Obese (NZO) mice.

Methods:

New Zealand Obese mice were maintained on either standard rodent chow or a low-carbohydrate and high-fat diet from 6 to 15 weeks of age. Body weight, food intake and blood glucose were assessed weekly. Blood glucose and insulin levels were also assessed after fasting and re-feeding and during an oral glucose tolerance test. The capacity of pancreatic β-cells to secrete insulin was assessed in vivo with an intravenous glucose tolerance test. β-Cell mass was assessed in histological sections of pancreata collected at the end of the study.

Results:

In New Zealand Obese mice, a low-carbohydrate and high-fat diet reduced plasma triglycerides but increased weight gain, adipose tissue mass, high-density lipoprotein cholesterol and exacerbated glucose intolerance. Although fasting insulin levels tended to be higher, insulin secretory function in low-carbohydrate and high-fat diet-fed mice was not improved nor was β-cell mass.

Conclusions:

A low-carbohydrate and high-fat diet is unlikely to be of benefit for preventing the decline in β-cell function associated with the progression of hyperglycemia in type 2 diabetes.

Can the paleolithic diet meet the nutritional needs of older people ?

A number of nutrient analyses of people following a paleo diet have been carried out, albeit mainly on younger subjects (<65 years). Protein intake on a paleo diet is generally found to be similar to or slightly higher than on a normal diet. This high protein intake would be particularly beneficial for the elderly because their protein requirements for maintaining muscle mass and preventing sarcopenia may be higher than those recommended for the general population ²⁹. Advice for the elderly on consuming meat as the main source of protein – as is the case in the paleo diet – is, however, controversial ³⁰.

As might be predicted from the high intake of fruit and vegetables in the paleo diet, some micronutrients, including vitamins C and E and β-carotene, are consumed in high quantities, while sodium intake has been found to be substantially lower than in control diets ³¹, ³². However, several short term clinical studies have found that calcium intake in subjects following a paleo diet is low, ranging from 355 to 395 mg/day ³³, ³¹, ³². Although, the optimal level of calcium intake required specifically to reduce the risk of osteoporotic fractures is currently the subject of considerable debate ³⁴, these values are nevertheless well below current recommended daily intake levels for healthy adults (700 mg in the UK and 1200 mg in the US).

The paleo diet’s low calcium content is probably attributable to the absence of dairy and cereals, which the UK National Diet and Nutrition Survey found contributed 42% and 29% respectively to the intake of calcium in the over 65’s ³⁵. It has been estimated that, for the US, adequate intake for calcium is not possible with dairy-free diets while also meeting other nutrient recommendations ³⁶. Modeling studies on the paleo diet have also confirmed its difficulties in meeting current recommended intakes of calcium ³⁷. Although calcium supplements are an option, these are at odds with the basic philosophy of the paleo diet as one reflecting a Stone Age diet.

Dairy is also the main dietary source of iodine – essential for thyroid hormone production. In the one study that has examined this, iodine intake on the paleo diet was only about half the UK recommended requirement of 140 μg/day ³¹. Some types of fish and shellfish are also good sources of iodine but – at least in this study – these did not compensate for the shortfalls. Iodised salt is available, but its iodine content is low, availability of this product is poor in some countries like the UK  ³⁸, and the paleo diet discourages added salt. Increased salt consumption is not advisable, in any case.

Dairy and cereals are also important sources of other micronutrients, including some (thiamine, riboflavin and iron) that have been reported to be reduced in some studies of the paleo diet. Most of these nutritional assessments of the paleo diet are based on young or middle aged subjects, but they do nevertheless raise concerns that the absence of dairy products and cereals will prevent adequate intake of some key micronutrients for the elderly. Although micronutrient deficiencies frequently occur in the elderly who do not follow a paleo diet, it does seem likely that the absence of dairy and cereals in this diet will exacerbate the risk of deficiencies. Dairy also provides protein in the omnivore diet without the need to trade off against cancer risks, as is the case with red meat.

The paleo diet has been reported to induce a feeling of satiety. This may be a useful short term strategy to lose weight ³⁹, but for many elderly people poor appetite is a significant concern, so the benefit of a diet with high satiety is questionable. In addition, the acceptability of any diet is key to compliance, and there are anecdotal comments on the difficulty of adhering to a paleo diet as it lacks many of the sources of carbohydrates (bread, pasta, etc.) that form a major part of many western meals ⁴⁰.

Long term studies on the health consequences of adhering to a paleo diet may currently be lacking ⁴¹. The knowledge we have is that the healthiest diet is one based on minimally processed foods, mostly coming from plant foods ⁴². Currently the diet with the strongest evidence for preventing nutrient deficiencies and protecting long term health, including in the elderly, is the plant-based Mediterranean diet ⁴³.

Why you might follow a paleo diet ?

You might choose to follow a paleo diet because you:

• You Want to Lose Weight or Maintain a Healthy Weight,
• Want help planning meals

Details of a Paleo Diet:

Paleolithic people ate no dairy food. Imagine how difficult it would be to milk a wild animal, even if you could somehow manage to catch one.

• Paleolithic people hardly ever ate cereal grains. This sounds shocking to us today, but for most ancient people, grains were considered starvation food at best.
• Paleolithic people didn’t salt their food.
• The only refined sugar Paleolithic people ate was honey, when they were lucky enough to find it.
• Wild, lean animal foods dominated Paleolithic diets, so their protein intake was quite high by modern standards, while their carbohydrate consumption was much lower.
• Virtually all of the carbohydrates Paleolithic people ate came from nonstarchy wild fruits and vegetables. Consequently, their carbohydrate intake was much lower and their fiber intake much higher than those obtained by eating the typical modern diet.
• The main fats in the Paleolithic diets were healthful, monounsaturated, polyunsaturated, and omega 3 fats—not the trans fats and certain saturated fats that dominate modern diets.
• The Paleo Diet is a low-carbohydrate diet—but that’s where any resemblance to the low-carbohydrate fad diets ends. Remember, the Paleo Diet is the only diet based on millions of years of nutritional facts—the one ideally suited to our biological needs and makeup and the one that most closely resembles hunter-gatherer diets.

How does the Paleo Diet compare with the low-carb fad diets and the average U.S. diet (the Standard American Diet) ?

People in the Paleolithic Age ate a lot of monounsaturated fats; they had saturated and polyunsaturated fats in moderation—but when they did have polyunsaturated fats, they had a proper balance of the omega 3 and omega 6 fats. They consumed far fewer omega 6 polyunsaturated fats than we do today. In addition, the main saturated fat in wild animals was healthful stearic acid, not the cholesterol-raising palmitic acid, which dominates the fat of feedlot cattle. Avoid fatty processed meats such as bacon, hot dogs, lunch meats, salami, bologna, and sausages because they contain excessive saturated fats, which raise your blood cholesterol levels.

• A paleo diet is rich in vegetables, fruits and nuts — all elements of a healthy diet.

The primary difference between the paleo diet and other healthy diets is the absence of whole grains and legumes, which are considered good sources of fiber, vitamins and other nutrients. Also absent for the diet are dairy products, which are good sources of protein and calcium.

These foods not only are considered healthy but also are generally more affordable and accessible than such foods as wild game, grass-fed animals and nuts. For some people, a paleo diet may be too expensive.

Recommendations vary among commercial paleo diets, and some diet plans have stricter guidelines than others. In general, paleo diets follow these guidelines.

What to eat

• Fruits
• Vegetables
• Nuts and seeds
• Lean meats, especially grass-fed animals or wild game
• Fish, especially those rich in omega-3 fatty acids, such as salmon, mackerel and albacore tuna
• Oils from fruits and nuts, such as olive oil or walnut oil

Here are some LEAN high protein foods that are part of the Paleo Diet:

• Skinless turkey breast (94 percent protein)
• Shrimp (90 percent protein)
• Red snapper (87 percent protein)
• Crab (86 percent protein)
• Halibut (80 percent protein)
• Beef sweetbreads (77 percent protein)
• Steamed clams (73 percent protein)
• Lean pork tenderloin (72 percent protein)
• Beef heart (69 percent protein)
• Broiled tuna (68 percent protein)
• Veal steak (68 percent protein)
• Sirloin beef steak (65 percent protein)
• Chicken livers (65 percent protein)
• Skinless chicken breasts (63 percent protein)
• Beef liver (63 percent protein)
• Lean beef flank steak (62 percent protein)
• Lean pork chops (62 percent protein)
• Mussels (58 percent protein)

You can get plenty of health-sustaining omega 3 fats from many foods found in the supermarket, such as:

• Fish and seafood, particularly cold-water fish such as salmon, mackerel, herring, and halibut
• Flaxseed oil, which can be used in several ways—as an ingredient in salad dressings, poured over steamed vegetables, or taken as a supplement
• Liver
• Game meat
• Free-range chickens
• Pasture-fed beef
• Eggs enriched with omega 3
• Salt-free walnuts and macadamia nuts (which are also tasty in salads)
• Leafy green vegetables
• Fish oil capsules, available at health food stores

What to avoid

• Grains, such as wheat, oats and barley
• Legumes, such as beans, lentils, peanuts and peas
• Dairy products
• Refined sugar
• Salt
• Potatoes
• Highly processed foods in general

A typical day’s menu

• Breakfast. Broiled salmon and cantaloupe.
• Lunch. Broiled lean pork loin and salad (romaine, carrot, cucumber, tomatoes, walnuts and lemon juice dressing).
• Dinner. Lean beef sirloin tip roast, steamed broccoli, salad (mixed greens, tomatoes, avocado, onions, almonds and lemon juice dressing) and strawberries for dessert.
• Snacks. An orange, carrot sticks or celery sticks.

The diet also emphasizes drinking water and being physically active every day.

The bottom line

A paleo diet may help you lose weight or maintain your weight. It may also have other beneficial health effects. However, there are no long-term clinical studies about the benefits and potential risks of the diet.

You might be able to achieve the same health benefits by getting enough exercise and eating a balanced, healthy diet with a lot of fruits and vegetables.

1. J Diabetes Sci Technol. 2009 Nov; 3(6): 1229–1232. Published online 2009 Nov. doi: 10.1177/193229680900300601. The Beneficial Effects of a Paleolithic Diet on Type 2 Diabetes and Other Risk Factors for Cardiovascular Disease. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2787021/[↩][↩][↩]
2. Evolutionary health promotion: a consideration of common counterarguments. Eaton SB, Cordain L, Lindeberg S. Prev Med. 2002 Feb; 34(2):119-23. https://www.ncbi.nlm.nih.gov/pubmed/11817904/[↩]
3. Evolution of the human diet: linking our ancestral diet to modern functional foods as a means of chronic disease prevention.
   Jew S, AbuMweis SS, Jones PJ. J Med Food. 2009 Oct; 12(5):925-34. https://www.ncbi.nlm.nih.gov/pubmed/19857053/[↩]
4. National Cancer Institute. Red Meat Consumption. https://progressreport.cancer.gov/node/27[↩]
5. National Cancer Institute, Division of Cancer Epidemiology & Genetics. Meat Intake. https://dceg.cancer.gov/research/what-we-study/meat-intake[↩][↩]
6. Lippi, G., Mattiuzzi, C., and Cervellin, G. Meat consumption and cancer risk: a critical review of published meta-analyses. Crit. Rev. Oncol. Hematol. 2016; 97: 1–14. http://www.croh-online.com/article/S1040-8428(15)30078-0/fulltext[↩]
7. National Cancer Institute. Chemicals in Meat Cooked at High Temperatures and Cancer Risk. https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/cooked-meats-fact-sheet[↩][↩]
8. Hoffman, R. and Gerber, M. Food processing and the Mediterranean diet. Nutrients. 2015; 7: 7925–7964[↩]
9. Knowler WC, Barrett-Connor E, Fowler SE, et al. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med 2002; 346: 393-403.[↩]
10. Pan XR, Li GW, Hu YH, et al. Effects of diet and exercise in preventing NIDDM in people with impaired glucose tolerance. The Da Qing IGT and Diabetes Study. Diabetes Care 1997; 20: 537-544.[↩]
11. Tuomilehto J, Lindstrom J, Eriksson JG, et al. Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance. N Engl J Med 2001; 344: 1343-1350.[↩]
12. Steven S, Hollingsworth KG, Al-Mrabeh A, et al. Very-low-calorie diet and 6 months of weight stability in type 2 diabetes: pathophysiologic changes in responders and nonresponders.
    Diabetes Care 2016; 39: 808-815.[↩]
13. Gunton JE, Cheung NW, Davis TM, et al. A new blood glucose management algorithm for type 2 diabetes: a position statement of the Australian Diabetes Society. Med J Aust 2014; 201: 650-653. https://www.mja.com.au/journal/2014/201/11/new-blood-glucose-management-algorithm-type-2-diabetes-position-statement[↩]
14. Andrikopoulos, S. The Paleo diet and diabetes. Med. J. Aust. 2016; 205: 151–152. https://www.mja.com.au/journal/2016/205/4/paleo-diet-and-diabetes[↩][↩]
15. Cardiovasc Diabetol. 2009 Jul 16;8:35. doi: 10.1186/1475-2840-8-35. Beneficial effects of a Paleolithic diet on cardiovascular risk factors in type 2 diabetes: a randomized cross-over pilot study. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2724493/[↩][↩][↩][↩]
16. Moderate carbohydrate, moderate protein weight loss diet reduces cardiovascular disease risk compared to high carbohydrate, low protein diet in obese adults: A randomized clinical trial. Lasker DA, Evans EM, Layman DK. Nutr Metab (Lond). 2008 Nov 7;5:30. doi: 10.1186/1743-7075-5-30. https://www.ncbi.nlm.nih.gov/pubmed/18990242/[↩]
17. Frassetto LA, Schloetter M, Mietus-Synder M, et al. Metabolic and
    physiologic improvements from consuming a Paleolithic, hunter-gatherer type diet. Eur J Clin Nutr 2009; 63: 947-955[↩]
18. Boers I, Muskiet FA, Berkelaar E, et al. Favourable effects of consuming a
    Palaeolithic-type diet on characteristics of the metabolic syndrome: a randomized controlled pilot-study. Lipids Health Dis 2014; 13: 160.[↩]
19. Lindeberg S, Jönsson T, Granfeldt Y, et al. A Palaeolithic diet improves glucose tolerance more than a Mediterranean-like diet in individuals with ischaemic heart disease.
    Diabetologia 2007; 50: 1795-1807.[↩]
20. Gannon MC, Nuttall FQ, Lane JT, et al. Effect of 24 hours of starvation on plasma glucose and insulin concentrations in subjects with untreated non-insulin-dependent diabetes mellitus. Metabolism 1996; 45: 492-497.[↩]
21. The effect of transition from traditional to urban life-style on the insulin secretory response in Australian Aborigines. O’Dea K, Spargo RM, Akerman K. Diabetes Care. 1980 Jan-Feb; 3(1):31-7. https://www.ncbi.nlm.nih.gov/pubmed/6996966/[↩]
22. Marked improvement in carbohydrate and lipid metabolism in diabetic Australian aborigines after temporary reversion to traditional lifestyle. O’Dea K. Diabetes. 1984 Jun; 33(6):596-603. https://www.ncbi.nlm.nih.gov/pubmed/6373464/[↩][↩]
23. A Palaeolithic diet improves glucose tolerance more than a Mediterranean-like diet in individuals with ischaemic heart disease.
    Lindeberg S, Jönsson T, Granfeldt Y, Borgstrand E, Soffman J, Sjöström K, Ahrén B. Diabetologia. 2007 Sep; 50(9):1795-807. https://www.ncbi.nlm.nih.gov/pubmed/17583796/[↩]
24. Effects of a short-term intervention with a paleolithic diet in healthy volunteers. Osterdahl M, Kocturk T, Koochek A, Wändell PE. Eur J Clin Nutr. 2008 May; 62(5):682-5. https://www.ncbi.nlm.nih.gov/pubmed/17522610/[↩]
25. Metabolic and physiologic improvements from consuming a paleolithic, hunter-gatherer type diet. Frassetto LA, Schloetter M, Mietus-Synder M, Morris RC Jr, Sebastian A. Eur J Clin Nutr. 2009 Aug; 63(8):947-55. https://www.ncbi.nlm.nih.gov/pubmed/19209185/[↩]
26. A Paleolithic diet confers higher insulin sensitivity, lower C-reactive protein and lower blood pressure than a cereal-based diet in domestic pigs. Jönsson T, Ahrén B, Pacini G, Sundler F, Wierup N, Steen S, Sjöberg T, Ugander M, Frostegård J, Göransson L, Lindeberg S. Nutr Metab (Lond). 2006 Nov 2;3:39. https://www.ncbi.nlm.nih.gov/pubmed/17081292/[↩]
27. Nutr Res. 2015 Jun;35(6):474-9. doi: 10.1016/j.nutres.2015.05.002. Epub 2015 May 14. Paleolithic nutrition improves plasma lipid concentrations of hypercholesterolemic adults to a greater extent than traditional heart-healthy dietary recommendations. https://www.ncbi.nlm.nih.gov/pubmed/26003334/[↩]
28. Nature’s Nutrition & Diabetes Journal (2016) 6, e194; doi:10.1038/nutd.2016.2. Published online 15 February 2016. A low-carbohydrate high-fat diet increases weight gain and does not improve glucose tolerance, insulin secretion or β-cell mass in NZO mice. http://www.nature.com/nutd/journal/v6/n2/full/nutd20162a.html[↩]
29. Bauer, J., Biolo, G., Cederholm, T., Cesari, M., Cruz-Jentoft, A.J., Morley, J.E. et al. Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE study group. J. Am. Med. Dir. Assoc. 2013; 14: 542–559. http://www.jamda.com/article/S1525-8610(13)00326-5/fulltext [↩]
30. Kouvari, M., Tyrovolas, S., and Panagiotakos, D.B. Red meat consumption and healthy ageing: a review. Maturitas. 2016; 84: 17–24. http://www.maturitas.org/article/S0378-5122(15)30078-5/fulltext[↩]
31. Genoni, A., Lyons-Wall, P., Lo, J., and Devine, A. Cardiovascular: metabolic effects and dietary composition of ad-libitum Paleolithic vs. Australian guide to healthy eating diets: a 4-week randomised trial. Nutrients. 2016; 8: 314–327[↩][↩][↩]
32. Osterdahl, M., Kocturk, T., Koochek, A., and Wandell, P.E. Effects of a short-term intervention with a paleolithic diet in healthy volunteers. Eur. J. Clin. Nutr. 2008; 62: 682–685. https://www.ncbi.nlm.nih.gov/pubmed/17522610?dopt=Abstract[↩][↩]
33. Jonsson, T., Granfeldt, Y., Ahren, B., Branell, U.C., Palsson, G., Hansson, A. et al. Beneficial effects of a Paleolithic diet on cardiovascular risk factors in type 2 diabetes: a randomized cross-over pilot study. Cardiovasc. Diabetol. 2009; 8: 35–49. https://www.ncbi.nlm.nih.gov/pubmed/19604407?dopt=Abstract[↩]
34. Reid, I.R. and Bristow, S.M. Calcium fortified foods or supplements for older people. Maturitas. 2016; 85: 1–4. http://www.maturitas.org/article/S0378-5122(15)30084-0/fulltext[↩]
35. B. Bates, A. Lennox, A. Prentice, et al. https://www.gov.uk/government/statistics/national-diet-and-nutrition-survey-results-from-years-1-to-4-combined-of-the-rolling-programme-for-2008-and-2009-to-2011-and-2012[↩]
36. Gao, X., Wilde, P.E., Lichtenstein, A.H., and Tucker, K.L. Meeting adequate intake for dietary calcium without dairy foods in adolescents aged 9 to 18 years (National Health and Nutrition Examination Survey 2001–2002). J. Am. Diet. Assoc. 2006; 106: 1759–1765. http://jandonline.org/article/S0002-8223(06)01843-8/fulltext[↩]
37. Metzgar, M., Rideout, T.C., Fontes-Villalba, M., and Kuipers, R.S. The feasibility of a Paleolithic diet for low-income consumers. Nutr. Res. 2011; 31: 444–451. http://www.nrjournal.com/article/S0271-5317(11)00096-0/fulltext[↩]
38. Bath, S.C., Button, S., and Rayman, M.P. Availability of iodised table salt in the UK – is it likely to influence population iodine intake. Public Health Nutr. 2014; 17: 450–454[↩]
39. Jonsson, T., Granfeldt, Y., Erlanson-Albertsson, C., Ahren, B., and Lindeberg, S. A paleolithic diet is more satiating per calorie than a mediterranean-like diet in individuals with ischemic heart disease. Nutr. Metab. (Lond.). 2010; 7: 85–99. https://www.ncbi.nlm.nih.gov/pubmed/21118562?dopt=Abstract[↩]
40. Jonsson, T., Granfeldt, Y., Lindeberg, S., and Hallberg, A.C. Subjective satiety and other experiences of a Paleolithic diet compared to a diabetes diet in patients with type 2 diabetes. Nutr. J. 2013; 12: 105–112[↩]
41. Maturitas, The European Menopause Journal. January 2017Volume 95, Pages 63–64. Can the paleolithic diet meet the nutritional needs of older people ? http://www.maturitas.org/article/S0378-5122(16)30222-5/fulltext[↩]
42. Katz, D.L. and Meller, S. Can we say what diet is best for health. Annu. Rev. Public Health. 2014; 35: 83–103[↩]
43. Gerber, M. and Hoffman, R. The Mediterranean diet: health, science and society. Br. J. Nutr. 2015; 113: S4–S10[↩]