Why the Calorie Approach to Weight Loss Doesn’t Work
Restricting calories to lose weight over the long term is more detrimental to your metabolism because it will turn your body into a hormone-induced hunger machine. A study in the New England Journal of Medicinefound that after putting overweight individuals on a ten-week calorie-restricted diet of 550 calories a day, they experienced elevated levels of the hormones ghrelin, which stimulates hunger, and gastric inhibitory polypeptide, which promotes fat storage. Leptin, a hormone that suppresses hunger and boosts fat burning, was profoundly reduced after the ten-week diet and stayed that way for the duration of the one-year study.Take note that after the ten-week diet, participants lost 30 pounds, but due to the way they had severely altered their metabolic hormone responses to food by restricting calories, they regained an average of 15 pounds in the next year.
The Thermic Effect of Food: Calories Are Stupid
A number of mainstream media outlets incorrectly (or stupidly) took the results of a new study published in the Journal of the American Medical Association proclaiming, “It’s the calories, stupid” that dictate body composition and weight gain. A close look at the study clarifies the misinterpretation and tells us exactly the opposite: it’s primarily the macronutrient content of the food you eat that dictates body composition, but if you overeat every day, then you will get fat.
The study compared the effect of overeating on body composition and fat gain from diets with three different protein contents. The thermic effect of the different diets was also measured, which is the amount of calories required to break down food, synthesize enzymes, and perform metabolic processes.
Participants ate either 5, 15, or 25 percent of their diet from protein with a whopping extra 954 calories a day for eight weeks. All the diets consisted of well over 3,000 calories a day and the macronutrient content was as follows:
All three groups gained the same amount of fat from the overeating—about 3.5 kg. The normal- and high-protein diet groups actually gained 0.2 kgs less than the low-protein group, but this was not statistically significant. What was most interesting was that the low-protein diet group gained the least total body weight because along with the 3.5 kg of fat gain, they lost almost a kilogram of muscle mass. The lack of amino acid building blocks in the diet put them into a severely catabolic, fat-storing state.In comparison, the normal-protein diet group gained 2.9 kg of muscle mass and the high-protein diet group gained 3.4 kg of muscle. Therefore, along with the nearly 3.5 kg of fat they gained, the normal- and high-protein diets did produce more weight gain. But, from a body composition viewpoint, the normal- and high-protein diets were better even though participants gained more total weight than the low-protein group because their percentage of body fat went down.
Most significant, this study shows the extreme variation in the amount of calories burned on a daily basis from eating different proportions of macronutrients. The resting metabolic rate (RMR) is the amount of calories burned at rest during the day, and it’s highly influenced by dietary makeup and the thermic effect of food. The group that ate the low-protein diet experienced a 2 percent drop in their metabolic rate, meaning they burned less calories each day just from eating a low-protein diet.In contrast, the normal- and high-protein diets increased RMR by 11 percent in response to the higher protein intake. This meant that by eating more protein, more of the energy consumed was turned into lean mass, and only about 50 percent of the energy consumed was turned into fat. Researchers estimate that more than 90 percent of the energy consumed in the low-protein group was turned into fat.
Whole and Processed Calories Aren’t the Same Either
A second study shows that the RMR and the thermic effect of eating whole foods is much higher than if you ate the exact same amount of calories from processed foods. This study compared the effect of a whole foods meal with a processed foods meal that contained equal calories and equal macronutrient content.
The thermic effect of the whole food meal was almost double that of the processed food meal. Participants burned 50 percent more calories after eating whole foods! Equally significant is that the participants who ate the processed food meal had their metabolic rates drop below their average RMR during the fourth hour after eating, while the whole food meal group never fell below the RMR. Also the duration of elevated energy expenditure from digestion in the whole food meal group lasted an hour longer than the processed food group.
Still Not Convinced? Check Out What Happened to the Pima Indians
The Pima Indians, natives of Arizona, provide a classic example of how body composition is affected by much more than just the amount of calories ingested each day. The Pima Indians have genotypically evolved eating a low number of calories, primarily from fish, small game, and foods they gathered. As early as 1901, a new “obesity epidemic” was evident among the Pima.
Local scientists who lived in the region were stumped as to why this indigenous group that had previously been “tall and sinewy” were now plagued by widespread obesity. More recent analysis has shown that shortly after the Pima came in contact with white settlers and adopted their foods—both foods that they began to grow such as corn, beans, potatoes, and processed foods like sugar, bread, and eventually soda—obesity became very common as did type 2 diabetes.
Analysis of changes in the Pima diet shows that the Pima were not overeating or ingesting more calories than previously when they adopted the “white man’s” diet of sugar, bread, starchy foods, eggs, and beef rather than fish and small game. Nor was their caloric intake greater than the amount of energy they burned on a daily basis. Rather, the Pima were eating the wrong type of calories for their genotype and it was causing a hormonal response that led to fat gain and diabetes.
For optimal body composition, the solution to any remaining confusion about how to adopt a diet for fat loss is to understand the following: