Not all calories are the same: a dietitian explains how the types of foods you eat are important to your body

Not all calories are the same: a dietitian explains how the types of foods you eat are important to your body


Even if two foods share the same number of calories, there can be significant differences in how they affect your body.

A calorie is a calorie is a calorie, at least from a thermodynamic point of view. It is defined as the amount of energy needed to raise the temperature of 1 kilogram of water by 1 degree

The Celsius scale, also known as the Celsius scale, is a temperature scale named after the Swedish astronomer Anders Celsius. On the Celsius scale, 0 ° C is the freezing point of water and 100 ° C is the boiling point of water at 1 atm pressure.

“> Celsius (2.2 pounds by 1.8 degrees

The Fahrenheit scale is a temperature scale, named after the German physicist Daniel Gabriel Fahrenheit and based on one he proposed in 1724. On the Fahrenheit temperature scale, the freezing point of frozen water is 32 °. F and water boils at 212 ° F, a separation of 180 ° F, as defined at sea level and standard atmospheric pressure.

“> Fahrenheit).

But when it comes to your body’s health and energy balance, not all calories are the same.

For example, some studies have shown that diets high in protein, low in carbohydrates, or a combination of both, result in greater weight loss than diets with other levels of fat, protein, and carbohydrates.

If all the calories in food were the same, don’t expect to see differences in weight loss between people who eat the same number of calories that are distributed in different types of food.

Dietitians like me know that there are many factors that influence what a calorie means to your body. This is what we understand about calories and nutrition so far.

Really available energy for your body

In the late 1800’s, chemist WO Atwater and his colleagues devised a system for figuring out how much energy, that is, how many calories, various foods contain. Basically, it burned food samples and recorded how much energy they released in the form of heat.

However, not all of the energy from food that can be burned in the lab is available to your body. What scientists call metabolizable energy is the difference between the total energy of food consumed and the energy that comes out of your body, undigested, in the feces and urine. For each of the three macronutrients (protein, carbohydrate, and fat), Atwater devised a percentage of the calories they contained that would be metabolizable.

Table of calorie macronutrients

According to the Atwater system, it is estimated that one gram of each macronutrient provides a certain number of calories. The U.S. Department of Agriculture still uses these calculations today to get an official number of calories for each food.

How much energy do you use

What you eat can affect what scientists call your body’s energy expenditure. This is the amount of energy you need to stay alive (energy you use to breathe, digest, keep your blood flowing, etc.), along with what you do to move your body. You may have heard this referred to as metabolism.

The quality of the diet can alter the body’s energy expenditure, which is also called the thermal effect of food. For example, in one study, people who ate the same number of calories a day but had a low-carb diet or a low-fat diet had differences in total energy expenditure of about 300 calories per day. Those who ate very low carb diets used more energy, while those who ate low fat diets used less.

In another study, high-fat diets resulted in lower overall energy expenditure than high-carbohydrate diets. Other researchers reported that while replacing carbohydrates with fats did not alter energy expenditure, people who increased their protein intake by 30% -35% of their diet used more energy.

Nutritional data Food labels

Nutrition Facts Food labels contain much more than just a calorie count, for good reason.

In general, diets rich in carbohydrates, fats or both produce an increase of 4% -8% in energy expenditure, while foods rich in protein cause an increase of 11% -14% above the resting metabolic rate. Proteins have a higher thermal effect because it is more difficult for the body to break down. While these variations are not huge, they could contribute to the obesity epidemic by encouraging a subtle mean weight gain.

Quality of the calories you eat

Dietitians pay attention to the glycemic index of a food and the glycemic load, that is, how quickly and how much it will increase blood glucose levels. An increase in blood glucose triggers the release of insulin, which in turn influences energy metabolism and the storage of excess energy as fat.

Foods such as white rice, cakes, cookies and chips have a high glycemic index / load. Green vegetables, raw peppers, mushrooms and legumes have a low glycemic index / load. There is some evidence to suggest that foods with a lower glycemic index / load may be better at keeping blood sugar levels regulated, regardless of the calories they contain.

Brain reward centers light up when people eat high-glycemic / high-load foods, highlighting the pleasurable and addictive effect of foods such as sweets or white bread.

The fiber content of food is another thing to keep in mind. Your body cannot digest fiber, which is found in plant foods such as fruits, vegetables, whole grains, and beans, for energy. Thus, high-fiber foods tend to have less metabolizable energy and can help you feel full of fewer calories.

Friends having dinner

Food provides more than calories.

Empty calories, those of foods with minimal or no nutritional value, are another factor to consider. Things like white sugar, soft drinks and many ultra-processed snacks do not provide much, if any, benefits in the form of protein, vitamins or minerals along with their calories. The opposite would be nutrient-dense foods that are high in nutrients or fiber, even though they are still relatively low in calories. Examples are spinach, apples and beans.

And don’t think empty calories are neutral. Nutritionists consider them harmful calories because they can have a negative effect on health. The foods that contribute most to weight gain are chips, potatoes, sugary drinks, and meats, both processed and unprocessed. On the other hand, foods that are inversely associated with weight gain are vegetables, whole grains, fruits, nuts, and yogurt.

More for health than calories and weight

It is undisputed that for weight loss, the difference between the number of calories consumed and the number of calories exercised through exercise is the most important factor. But don’t be fooled. While weight plays an important role in health and longevity, weight loss alone is not the same as health.

Yes, some high-protein diets seem to promote weight loss at least in the short term. But epidemiologists know that in areas where people live longer, about 100 years on average, they eat a mainly vegetable diet, with very low or no protein of animal origin and low or moderate fat in the form of monkey and polyunsaturated. fats.

I often hear friends or clients say things like “these are the ones that make me fat” or “I have to go on a low carb diet.” But these complaints drive dieters like me crazy. Carbohydrates include foods such as Coca-Cola and candy canes, but also apples and spinach. Reducing simple carbs like soft drinks, refined flour bakery items, pasta and sweets will certainly have a positive impact on your health. But eliminating carbohydrates like vegetables and fruits will have the opposite effect.

A plant-rich diet rich in plant-based protein and carbohydrates, mainly from vegetables, fruits, nuts, and legumes, is the healthiest diet known to researchers for longevity and the prevention of chronic diseases such as heart disease. , cancer, hypertension and many other conditions.

The modern Western diet suffers from an increase in the amount of calories consumed with a simultaneous decrease in the quality of calories consumed. And researchers now know that the calories in different foods have different effects on fullness, insulin response, the process of converting carbohydrates into body fat, and metabolic energy expenditure.

When it comes to your health, count on the quality of the calories you consume rather than the calorie count.

Written by Terezie Tolar-Peterson, Associate Professor of Food Science, Nutrition and Health Promotion, Mississippi State University.

This article was first published in The Conversation.The conversation


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