The Truth About Calories

What are Calories ?

Calories are units representing the ability of food to be converted by the body into energy. All food contains calories, and we need a certain amount of calories each day.

• Large calorie (Cal) is the energy needed to increase 1 kg of water by 1°C at a pressure of 1 atmosphere.
• Large calorie (Cal) is also called Food calorie and is used as a unit of food energy.
• 1 Large Calorie (1 kilocalories) = 4.184 kilojoules (kJ)
• 2000 Calories = 8368 kilojoules (kJ)

Because how much calories you eat and what food groups you need are highly dependent on your age, sex, and your level of physical activity. For the most accurate way calculate how much food and calories you need to eat per day from each food group >>> Go to the United States Department of Agriculture’s MyPlate Daily Checklist ¹⁾ >>> https://www.choosemyplate.gov/myplate-daily-checklist-input
Simply enter your age, sex, height, weight, and physical activity level to get a plan that’s right for you. The MyPlate Daily Checklist shows your food group targets – what and how much to eat within your calorie allowance.

You can also try the National Institute of Diabetes and Digestive and Kidney Diseases — Body Weight Planner ²⁾.  Find out your daily calorie needs or goals with the Body Weight Planner ³⁾.

Calories are the energy in food. Your body has a constant demand for energy and uses the calories from food to keep functioning. Energy from calories fuels your every action, from sleeping to marathon running.

It is true that all “calories” have the same amount of energy. One dietary Calorie contains 4184 Joules of energy. In that respect, a calorie is a calorie. But when it comes to your body, things are not that simple. Looking only at calories ignores the metabolic effects of each calorie; the source of the calorie changes how you digest it and how you retrieve energy from it. The human body is a highly complex biochemical system with elaborate processes that regulate energy balance. This is because some foods provide not only calories but also other ingredients that also are critically important, such as vitamins, minerals, antioxidants, and others. When a food provides primarily calories, and little else of value to our health, we say that food has “empty calories.”

Examples include beverages like sugary soda, and foods like buttery pastries. They provide little health value. You can get all the calories you need from foods other than these-foods that contain other healthful ingredients. Another problem with foods said to contain “empty calories” is that they usually contain lots of calories-more than we need to attain or sustain a healthy weight.

Counting calories alone doesn’t work because ultimately it matters where those calories come from; this matters more than the number of calories ingested.

Carbohydrates, fats and proteins are the types of nutrients that contain calories and are the main energy sources for your body. Regardless of where they come from, the calories you eat are either converted to physical energy or stored within your body as fat.

Your weight is a balancing act, but the equation is simple: If you eat more calories than you burn, you gain weight.

Because 3,500 calories equals about 1 pound (0.45 kilogram) of fat, you need to burn 3,500 calories more than you take in to lose 1 pound.

So, in general, if you cut 500 calories from your typical diet each day, you’d lose about 1 pound a week (500 calories x 7 days = 3,500 calories). A weight loss of 1 to 2 pounds a week is the typical recommendation. Although that may seem like a slow pace for weight loss, it’s more likely to help you maintain your weight loss for the long term. Remember that 1 pound (0.45 kilogram) of fat contains 3,500 calories. So to lose 1 pound a week, you need to burn 500 more calories than you eat each day (500 calories x 7 days = 3,500 calories).

However, it isn’t quite this simple,because you usually lose a combination of fat, lean tissue and water. Also, if you lose a lot of weight very quickly, you may not lose as much fat as you would with a more modest rate of weight loss. Instead, you might lose water weight or even lean tissue, since it’s hard to burn that many fat calories in a short period.

In some situations, however, faster weight loss can be safe if it’s done the right way. For example, the Mayo Clinic Diet has a quick-start phase in which you might lose 6 to 10 pounds in the first two weeks. You can lose weight quickly with an approach like this because it combines many healthy and safe strategies at once — no gimmicks or extreme dieting. After the initial two-week period, you transition into the recommended weight loss of 1 or 2 pounds a week, which is not only safe but also realistic and sustainable for the long term.

The “calorie myth” is one of the most pervasive and most damaging. It is the idea that calories are the most important part of the diet, that the sources of those calories don’t matter. For example, it may be quite easy to eat 500 calories (or more) of ice cream or sugary drinks, while you’d have to force feed yourself to eat 500 calories or 6.5 hard boiled eggs or 1.5kg of broccoli.

“A calorie is a calorie is a calorie,” they say… that it doesn’t matter whether you eat a 500 calories of sugar candy or broccoli, they will have the same effect on your weight.

These stored calories will remain in your body as fat unless you use them up, either by reducing calorie intake so that your body must draw on reserves for energy, or by increasing physical activity so that you burn more calories.

How Many Calories Do You Need ?

For a woman
1,600 calories	1,800 calories	2,000-2,200 calories
For a man
2,000-2,200 calories	2,200-2,400 calories	2,400-2800 calories

Estimated Calorie Requirements

Source: HHS/USDA Dietary Guidelines for Americans: 2005 ⁴⁾

• These levels are based on Estimated Energy Requirements from the Institute of Medicine Dietary Reference Intakes macronutrients report, 2002, calculated by gender, age, and activity level for reference-sized individuals. “Reference size,” as determined by IOM, is based on median height and weight for ages up to age 18 years of age and median height and weight for that height to give a BMI of 21.5 for adult females and 22.5 for adult males.
• Sedentary means a lifestyle that includes only the light physical activity associated with typical day-to-day life.
• Moderately active means a lifestyle that includes physical activity equivalent to walking about 1.5 to 3 miles per day at 3 to 4 miles per hour, in addition to the light physical activity associated with typical day-to-day life.
• Active means a lifestyle that includes physical activity equivalent to walking more than 3 miles per day at 3 to 4 miles per hour, in addition to the light physical activity associated with typical day-to-day life.
• The calorie ranges shown are to accommodate needs of different ages within the group. For children and adolescents, more calories are needed at older ages. For adults, fewer calories are needed at older ages.

Estimated Calorie Needs per Day, by Age, Sex, and Physical Activity Level

(SOURCE: ⁵⁾)

Balancing Calories

Balancing the calories you eat and drink with the calories burned by being physically active helps to maintain a healthy weight.

Each person uses different amounts of calories doing the same type of activity. In general, heavier people use more calories. Those who weigh less use fewer. Women also probably use fewer.

How much physical activity ? Although any amount of regular physical activity is good for you, aim for at least 150 minutes of physical activity each week. Unless you are already that active, you won’t do that much all at once—10-minute sessions several times a day on most days are fine.

Different foods go through different biochemical pathways, some of which are inefficient and cause energy (calories) to be lost as heat.

You should choose nutrient-dense foods. These foods give you lots of nutrients without a lot of extra calories. Even more important is the fact that different foods and macronutrients have a major effect on the hormones and brain centers that control hunger and eating behavior.

On the other hand, foods that are high in calories for the amount of food are called calorie dense. They may or may not have nutrients. High-calorie foods with little nutritional value, like potato chips, sugar-sweetened drinks, candy, baked goods, and alcoholic beverages, are sometimes called “empty calories.”

Energy density means getting more for your calories.

Energy density is the number of calories (energy) in a given amount (volume) of food. By choosing foods that are low in calories, but high in volume, you can eat more and feel fuller on fewer calories.

Fruits and vegetables are good choices because they tend to be low in energy density and high in volume.

So what about raisins ? They’re actually high in energy density — they pack a lot of calories into a small package. For example, 1/4 cup of raisins has about 100 calories. For about the same number of calories you could have 1 cup of grapes — and get more bite for your calorie buck.

High versus low energy density

Foods high in energy density include fatty foods, such as many fast foods, and foods high in sugar, such as sodas and candies. For example, a small order of fast-food french fries has about 250 calories.

For about the same calorie count, you could have heaping helpings of fresh fruits and vegetables — such as this salad made with 10 cups of spinach, 1 1/2 cups of strawberries and a small apple.

And with fresh fruits and vegetables, you get a plethora of valuable nutrients — not just empty calories. These foods also take longer to eat and are filling, which helps curb your hunger.

Another way to think about the idea of nutrient-dense and calorie-dense foods is to look at a variety of foods that all provide the same calories. Which would make a better snack for you ?

Let’s say that you wanted to have a snack that contained about 100 calories. You might choose one of these:

• 7- or 8-inch banana,
• Two ounces baked chicken breast with no skin,
• Three cups low-fat popcorn,
• Two regular chocolate-sandwich cookies,
• Half cup low-fat ice cream,
• One scrambled large egg cooked with fat,
• 20 peanuts,
• Half of the average-size candy bar.

Although these examples all have about 100 calories, there are some big differences:

• Banana, chicken, peanuts, or egg are more nutrient dense.
• Popcorn or chicken are likely to help you feel more satisfied.
• Chicken, peanuts, or egg have more protein.
• Cookies, candy, and ice cream have more added sugars.

Can choosing a nutrient-dense food instead of a calorie-dense food really make a difference ? Here are some examples of nutrient-dense choices side by side with similar foods that are not nutrient-dense, have more calories, or both.

A) Large apple, 8 oz.
110 calories

B) Apple pie, eighth of a 2-crust 9″ pie
356 calories

A) Two slices of 100% whole wheat bread, 1 oz. each
138 calories

B) Medium croissant, 2 oz.
231 calories

A) Medium baked potato with peel, 2 tablespoons low-fat sour cream
203 calories

B) French fries, one medium fast-food order
457 calories

A) Roasted chicken breast, skinless (3 oz.)
141 calories

B) Fried chicken wings with skin and batter, (3 oz.)
479 calories

Healthy eating:

• Emphasizes vegetables, fruits, whole grains, and fat-free or low-fat milk and milk products.
• Includes lean meat, poultry, fish, cooked dry beans and peas, eggs, and nuts.
• Is low in saturated fats, trans fats, salt, and added sugars.
• Balances the calories from foods and beverages with calories burned through physical activity so that you can maintain a healthy weight.

How To Read the Food Label

Reading labels can help you make good food choices. Processed and packaged foods and drinks—you’ll find them in cans, boxes, bottles, jars, and bags—have a lot of nutrition and food safety information on their labels or packaging.

Read labels as you shop. Pay attention to the serving size and the servings per container. All labels list total calories in a serving size of the product. Compare the total calories in the product you choose with others like it; choose the one that is lowest in calories.

Look for:

A) Product dates

You might see one of three types of product dates on some foods you buy:

• “Sell by” tells how long the store can sell foods like meat, poultry, eggs, or milk products—buy it before this date.
• “Use by” tells how long the food will be at peak quality—if you buy or use it after that date, some foods might not be safe any longer.
• “Best if used by” (or “best if used before”) tells how long the food has the best flavor or quality—it is not a purchase or safety date.

B) Ingredients list

This tells you everything that a processed food contains. Items are presented from largest to smallest ingredient. That is, there is more of the first ingredient listed on the label than any other ingredient. The last ingredient on the list is found in the smallest amount.

C) Nutrition Facts label

The U.S. Food and Drug Administration (FDA) requires a Nutrition Facts label on all processed food. You can find nutrition information for fresh vegetables and fruits.

The Nutrition Facts label is all white with black letters. You can see a sample label below, along with a few key things to know about it. To learn more about the information on this label, go to FDA’s Labeling and Nutrition. Note: The FDA recently proposed updates to the Nutrition Facts label to reflect the latest scientific information linking diet and chronic diseases like obesity and heart disease. Proposed updates include a new design that highlights key parts of the label such as calories and serving sizes.

• At the top, you will find the FDA definition of a serving of that food or drink and the number of servings in the container. The rest of the nutrition information on the label is for one serving, not for the whole package or bottle. If a can or package holds two servings and you eat the whole thing, you have eaten double all the numbers on the Nutrition Facts label—twice the calories, twice the fat, twice the protein, and so on.
• Daily Value (DV) is how much of each nutrient most people need each day. The %DV says what part (as a percent) of the total daily recommendation for a nutrient is in a serving. The Daily Value is based on eating 2,000 calories each day, so if you are eating fewer calories and eat a serving of this food, your %DV will be higher than you see on the label.

** Healthy Tip: If a food has 5% of the Daily Value or less, it is low in that nutrient. If it has 20% or more, it is high in that nutrient. Low or high can be either good or bad—it depends on whether you need more of a nutrient (like fiber), or less (like fat).

The foods we eat can have a huge impact on the biological processes that govern when, what and how much we eat.

Here are 6 proven examples of why a calorie is NOT a calorie.

1. Fructose vs Glucose

The two main simple sugars in the diet are glucose and fructose. These two seem almost identical. They have the same chemical formula and weigh the exact same. But to your body, the two are completely different.

Glucose can be metabolized by all of the body’s tissues, but fructose can only be metabolized by the liver in any significant amount.

Here are a few examples of why glucose calories are NOT the same as fructose calories:

-Ghrelin is the “hunger hormone.” It goes up when we’re hungry and down after we’ve eaten. One study shows that fructose leads to higher ghrelin levels (more hunger) than glucose.

-Fructose does not stimulate the satiety centers in the brain in the same way as glucose, leading to reduced satiety.

-A high consumption of fructose can cause insulin resistance, abdominal fat gain, increased triglycerides, blood sugar and small, dense LDL compared to the exact same number of calories from glucose. Same number of calories, vastly different effects on hunger, hormones and metabolic health. Because a calorie is not a calorie.

Keep in mind that this applies to fructose from added sugars only, not the fructose from fruit. Fruits also have fiber, water and significant chewing resistance, which mitigate the negative effects of the fructose.

Bottom Line: Even though fructose and glucose have the same chemical formula, fructose has much more negative effects on hormones, appetite and metabolic health.

2. The Thermic Effect of Food

Different foods go through different metabolic pathways. Some of these pathways are more “efficient” than others.

The more “efficient” a metabolic pathway is, the more of the food energy is used for work and less is dissipated as heat. The metabolic pathways for protein are less efficient than the metabolic pathways for carbs and fat.

Protein contains 4 calories per gram, but a large part of the protein calories are lost as heat when it is metabolized by the body.

The thermic effect of food is a measure of how much different foods increase energy expenditure, due to the energy required to digest, absorb and metabolize the nutrients.

This is the thermic effect of different macronutrients:

• Fat: 2-3%
• Carbs: 6-8%
• Protein: 25-30%

Sources vary on the exact numbers, but it is clear that protein requires much more energy to metabolize than fat and carbs.

If we go with a thermic effect of 25% for protein and 2% for fat, this would mean that a 100 calories of protein would end up as 75 calories, while a 100 calories of fat would end up as 98 calories. Put simply, high protein diets have a “metabolic advantage.”

Studies show that high protein diets boost metabolism by 80 to 100 calories per day, compared to lower protein diets.

There is also one study that compared two sandwich meals that had the same number of calories and macronutrients. However, one sandwich was made with whole grains and cheddar cheese, while the other was made with refined grains and processed cheese. Those who ate the whole grain sandwich burned twice as many calories digesting the meal.

Bottom Line: Protein calories are less fattening than calories from carbs and fat, because protein takes more energy to metabolize. Whole foods also require more energy to digest than processed foods. It is very clear that when it comes to metabolism and appetite regulation, a protein calorie is NOT the same as a carb calorie or a fat calorie.

3. Protein Kills Appetite and Makes You Eat Fewer Calories

The protein story doesn’t end with increased metabolism. It also leads to significantly reduced appetite, making you eat less calories automatically.

The studies showed that protein is the most fulfilling macronutrient by far. If people increase their protein intake, they start losing weight without counting calories or controlling portions. Protein puts fat loss on autopilot.

In one study, those who increased their protein intake to 30% of calories automatically started eating 441 fewer calories per day and lost 4.9 kg (11 lbs) in 12 weeks.

If you don’t want to go on a “diet” but simply tip the metabolic scales in your favor, then adding more protein to your diet may be the simplest (and most delicious) way to cause “automatic” weight loss.

Bottom Line: Increased protein can lead to drastically reduced appetite and cause automatic weight loss without the need for calorie counting or portion control.

4. The Satiety Index

The satiety index is a measure of the ability of foods to reduce hunger, increase feelings of fullness and reduce energy intake for the next few hours. There are many factors that determine the satiety value of different foods, which is measured on a scale called the satiety index. Different foods have different effects on satiety.

It is also much easier to overeat on some foods than others e.g. ice cream vs broccoli. This is a key example of how the food choices you make can have a huge impact on the total calories you end up consuming.

If you eat foods that are low on the satiety index, then you will be hungrier and end up eating more. If you choose foods that are high on the satiety index, you will end up eating less and losing weight.

Some examples of foods with a high satiety index are boiled potatoes, beef, eggs, beans and fruits, while foods that are low on the satiety index include donuts and cake.

Clearly, whether you choose fulfilling foods or not will have a major difference on energy balance over the long term. Because a calorie from a boiled potato is not the same as a calorie from a doughnut.

Bottom Line: Different foods have different effects on satiety and how many calories we end up consuming in subsequent meals. This is measured on a scale called the Satiety Index.

5. Low-Carb Diets Lead to Automatic Calorie Restriction

Since the year 2002, over 20 randomized controlled trials have compared low-carb and low-fat diets.

Healthy Foods — the studies consistently show that low-carb diets lead to more weight loss, often 2-3 times as much. One of the main reasons for this is that low-carb diets lead to drastically reduced appetite. People start eating less calories without trying. But even when calories are matched between groups, the low-carb groups usually lose more weight, although it doesn’t always reach statistical significance.

The biggest reason for this is probably that low-carb diets also cause significant water loss. Excess bloat tends to go away in the first week or two.

Another reason is that low-carb diets tend to include more protein than low-fat diets. Protein takes energy to metabolize and the body expends energy turning protein into glucose.

Bottom Line: Low-carb diets consistently lead to more weight loss than low-fat diets, even when calories are matched between groups.

6. The Glycemic Index

There are many controversies in nutrition and the experts don’t agree on many things. But one of the few things that almost everyone agrees on is that refined carbs are bad. This includes added sugars like sucrose and high fructose corn syrup, as well as refined grain products like white bread.

Refined carbohydrates tend to be low in fiber and they get digested and absorbed quickly, leading to rapid spikes in blood sugar. They have a high glycemic index (GI), which is a measure of how quickly foods raise blood sugar.

When we eat a food that spikes blood sugar fast, it tends to lead to a crash in blood sugar a few hours later, also known as the “blood sugar roller coaster.” When blood sugar crashes, we get cravings for another high-carb snack.

In a study that served people milkshakes who were identical in every respect except that one had high GI carbs while the other had low GI carbs, the high GI milkshake caused increased hunger and cravings compared to the low GI shake.

Another study found that teenage boys ate 81% more calories during a high GI meal compared to a low GI meal. So the speed at which carb calories hit the system can have a dramatic effect on their potential to cause overeating and weight gain.

If you’re on high-carb diet, it is crucial to choose whole, unprocessed carb sources that contain fiber. The fiber can reduce the rate at which the glucose enters your system. The studies consistently show that people who eat the most high glycemic index foods are at the greatest risk of becoming obese and diabetic. Because not all carb calories are created equal.

Bottom Line: Studies show that refined carbohydrates lead to faster and bigger spikes in blood sugar, which leads to cravings and increased food intake.

Dairy Products

Cereals, Grains, and Pastas

Meat, Fish, and Poultry

Baked Goods

Snacks and Sweets

Fats, Oils, and Salad Dressings

Miscellaneous

How To Burn Calories

You need to burn off calories to help maintain a healthy body weight for your size and age. You use some calories simply without thinking about it in your day-to-day activities. How active do you have to be beyond that ? There is no simple answer. The important thing to remember is that many people need to become more active than they are now and you might be one of them.

Each person uses different amounts of calories doing the same type of activity. In general, heavier people use more calories. Those who weigh less use fewer. Women also probably use fewer.

Experts do not know how the number of calories used during an activity differs for older people compared to those who are younger. As an example, if an average younger man—around 5’10”, 154 pounds—eats a wedge of apple pie for dessert (about 356 calories), how long would he have to ride a bicycle to burn off the calories ? More than an hour based on some estimates.

We don’t know if it’s the same for you, but whether you would have to ride even longer or a little less, that’s still a long time on a bike. And what if you ate an apple (about 110 calories) instead of that pie ? You’d have to spend less time on the bike to burn the calories.

You don’t have to spend a lot of money joining a gym or hiring a personal trainer. Think about the kinds of physical activities that you enjoy—for example, walking, running, bicycling, gardening, housecleaning, tennis, swimming, or dancing. Try to make time to do what you enjoy on most days of the week. And then increase how long you do it, or add another fun activity.

In Summary

Different calorie sources can have vastly different effects on hunger, hormones, energy expenditure and the brain regions that control food intake. Even though calories are important, counting them or even being consciously aware of them is not at all necessary to lose weight.

In many cases, simple changes in food selection can lead to the same (or better) results than calorie restriction.