Are all calories the same?
Are all calories equal?--A common debate in the fields of nutrition and the fitness industry. The debate refers to the idea that calories determine any weight changes and the sources of these calories do not matter.
Calories are a measurement of energy. In terms of energy, yes, 1000 calories, regardless of where they come from, are the same. Energy cannot be destroyed or created. One calorie is equivalent to 4.184 Joules. If more energy is consumed than is used, then the body stores the extra as fat. This is the laws of thermodynamics.
If all calories are equal, then why is chocolate considered “unhealthy” whereas salad is deemed “healthy” and is conducive to weight loss?
The main problem with the “calories in calories out” way of thinking is that it doesn’t take into account other factors that affect weight and health in general. Unfortunately, no matter how much we love chocolate and sweets, weight loss and our health are not all about calories. Weight loss is a lot more complicated than this. Let’s take a look at the other factors that come into play.
Thermogenic Effect of Food
Our total daily energy expenditure consists of three main parts, one of which is the “thermogenic effect of food”—to put it simply, the amount of energy it takes to digest the food we’ve eaten. Different macronutrients require different amount of energy to digest and absorb because they go through different metabolic pathways.
Protein takes the most energy to digest
Protein contain 4 calories per gram but 25-30% of the energy is burnt during the digestive process.
Carbs also contain 4 calories per gram but require only about 8-10% of the energy for digestion.
Fat contains 9 calories per gram but require merely 2-3% of energy to metabolize.
In other words, if you eat 100 calories of protein, you end up absorbing around 75 calories, whereas if you take in 100 calories from fat, you end up with 97 calories—this is an evidence that although all calories provide equal amounts of energy, the amount of calories we end up absorbing in the end is different.
Other than the thermogenic effect of food, the functions of different macronutrients also have an impact.
Fats slow down the digestion process and is also essential for the absorption of fat-soluble vitamins.
Protein helps keep you feeling satiated and is an important building block of the body and vital for maintaining muscles, which help with weight loss and the “toned” look.
Quality of Macronutrients
Even macronutrients are not created equal
Some fats are better than others--unsaturated fats, such as those found in avocados and seeds, are better than saturated fats and trans fat which have been linked to increased cholesterol, cardiovascular diseases and type 2 diabetes.
Proteins are not all equal either. Some are higher quality than others, helpful for reducing appetite and aiding muscle repair and recovery whereas lower quality protein such as processed meat contains branched-chain amino acids which contribute to health conditions such as diabetes.
Carbs are even more complex because there are different types of carbs—starches, sugars and fibers and they all metabolize very differently. Less processed carbs, such as fruits and vegetables, tend to be better in quality and fiber helps to slow the digestion process, making you feel fuller and longer. On the other hand, “empty calories” like chocolate provide hardly anything other than sugar and jeopardizes your health, increasing your risk of developing type 2 diabetes.
In terms of weight loss, of course you’d want fewer calories remaining for absorption while feeling satiated—for this reason, protein is a great choice.
Different foods and macronutrients affect hormones and brain receptors that control hunger. Our thoughts and actions are largely controlled by hormones. Eating is mostly subconscious and hunger and appetite are affected by hormones. Although someone can count calories, learn portion control or go on a diet in a bid to lose weight, you have to focus on these numbers wholeheartedly and need great determination as your body changes its hormone levels encouraging you to find food, thinking that you are in danger of starvation—this is often why people binge.
An example of the fact that hormones and physiology affect weight is medication—certain antidepressants, anti-cancer drugs and contraceptive pills are notorious for causing weight gain. These medications cause weight gain because they change hormone levels and how the brain receives hunger information, which increase calorie intake and eventually causing weight gain.
Refined carbohydrates tend to be low in fiber and are digested and absorbed quickly, spiking your blood sugar rapidly and making the blood sugar crash more noticeable and making you hunger and crave high-carb food again soon.
Calorie Density and Satiety
Some foods are much easier to overeat than others due to their calorie density and the blood sugar spike caused by it. It is easy to finish a whole bag of chocolate in one sitting, consuming well over 500 calories; however, it is very difficult to eat 500 calories of vegetables in one go.
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