For decades, we have been told that when it comes to weight gain, loss, and maintenance, a calorie is a calorie. Meaning, that a calorie — which is a specific amount of chemical energy — coming from an energy-yielding macronutrient (carbohydrates, proteins, fats or alcohol) will all function the same in the body. It also implied that a caloric intake of 2,000 calories will have the same impact on weight status, regardless of it’s composition (the respective ratios of carbs, proteins, fats and alcohol).
In the laboratory, yes, a calorie from carbohydrate contains exactly the same amount of chemical energy that a calorie from fat or protein does. Thankfully, our bodies are not laboratories and each macronutrient requires different amounts of energy to digest, and absorb, meaning that the net energy provided to the body from each macronutrient is different. This term is called dietary induced thermogenesis (DIT) or the thermic effect of food (TEF) and is the percentage of energy contained in that nutrient that is directly expended for digestion and absorption. The DIT of the macronutrients varies greatly: 0-3% for fat, 5-10% for carbohydrate, 20-30% for protein, and 10-30% for alcohol. The average DIT percentage for most people following the standard American diet is between 5-15%. Some factors that raise the DIT of a meal include the presence of fiber and the inclusion of protein, if both are included in a meal, the DIT will be higher and consequently fewer calories will be available for energy utilization or fat production.
In addition to its larger DIT, protein has a considerable effect on increasing satiety (the feeling of fullness, satisfaction, and lack of hunger between meals), while low glycemic index carbohydrates (vegetables, beans, and legumes, and fruit) increase both satiety and satiation (the signals your body sends telling you you’ve had enough food at a meal). Somewhat paradoxically, satiety is impeded by a high sugar (carbohydrate) intake, which illuminates the essential role of fiber in the carbohydrates we consume.
In addition to dampening satiety signals, high sugar/carbohydrate intake increases blood sugar, insulin, and inflammation, all of which are linked to weight gain, diabetes, obesity, and many other disease states. Carbohydrates, regardless of their source, all get digested into their monosaccharide or single sugar building block units. Even carbohydrates from quinoa will eventually be digested and absorbed as single sugar units. The difference between carbohydrates from a can of soda and the carbohydrates from a serving of quinoa is that the quinoa also contains ample amounts of fiber and some protein, both of which delay digestion and consequently the absorption of sugar into the bloodstream. Conversely, the sugar from the soda is immediately absorbed into the bloodstream and sends your blood glucose and insulin levels soaring. A calorie from sugar therefore, has an outsized negative impact on overall health than a calorie from protein or even healthy fats.
Finally, consider that when you consume protein, carbohydrate, and fat, you’re also ingesting varying amounts of fiber and essential micronutrients such as vitamins, minerals, and phytochemicals. This concept is called nutrient density, or the amount of nutrients you get per calorie. A nutrient-dense calorie maximizes the benefits to the body by providing essential proteins, fats, and carbohydrates along with high levels of vitamins, minerals, and phytochemicals. Therefore, for optimal health, create meals and snacks from the most nutrient-dense calorie sources:
- Dark leafy green vegetables (kale, spinach, swiss chard, collards, arugula, bok choy, beet greens),
- Cruciferous vegetables (broccoli, cauliflower, cabbage, brussels sprouts),
- Colorful root vegetables (beets, sweet potatoes, yams, carrots),
- Nuts and seeds (coconut, almonds, chia, flax, hemp),
- Legumes & beans (lentils, split peas, black beans, kidney beans, garbanzo beans),
- Wild-caught fish (salmon, halibut, sardines, anchovies),
- Pasture-raised animal products (eggs, cultured dairy(plain yogurt & kefir), beef, bison, poultry),
- Berries (blueberries, strawberries, huckleberries, blackberries),
- Anti-inflammatory fats (coconut oil, avocado oil, extra virgin olive oil, ghee, butter),
- Other fruit (bananas, apples, pears, pineapple, papaya),
- Whole grains (quinoa, wild rice, brown rice, teff, millet).