Index
When it comes to shedding pounds, the most important factor is eating less.
When you consume fewer calories than you expend, you will lose weight, and the diet that will help you lose weight will allow you to consume fewer calories without causing much distress or lethargy.
Your body weight depends on your total caloric intake rather than your macronutrient ratios (how many of your calories come from carbohydrates, protein, fat, and alcohol).
Increasing caloric intake as an independent variable is more than enough to explain the current obesity epidemic , without the need to find a scapegoat, such as high fructose corn syrup.
A trial in a controlled setting (a metabolic service) compared various isocaloric diets comprised of 15% protein, 15-85% carbohydrates, and 0-70% fat.
This study concluded that calorie restriction, and not macronutrient ratios, determined weight loss.
The comparison of low-carbohydrate and high-carbohydrate diets at 6 weeks and 12 weeks led to the same conclusion, as did the comparison of a low-fat / high-protein diet with a standard protein / high-fat diet.
Another test at a metabolic service noted that in healthy individuals who overeat for 8 weeks, caloric intake alone explains the increase in body fat.
However, caloric expenditure, total weight, and lean mass increased with protein as a percentage of caloric intake.
In contrast, a previous study on the impact of protein on weight loss noted that women lost both weight on a high-protein diet and on a high-carbohydrate diet, but that subjects with high triglycerides lost more fat in the high protein diet.
In people suffering from hyperinsulinemia, insulin resistance, or type 2 diabetes, the results are more or less the same: calorie restriction, no macronutrient ratios, leads to weight loss.
Two studies noted, however, that lean mass is better preserved in women (but not men) on a high-protein diet, and one study found greater weight loss (almost-protein group (men and women) ).
In conclusion, losing weight requires a negative energy balance, which can be obtained by eating less, as we have seen, but also by exercising more.
Regardless of the macronutrient ratios in your diet, a negative energy balance (consuming fewer calories than your body needs) is responsible for weight loss.
But what about fad diets?
Many diets, old-fashioned or not, work. This is mainly because they cut calories.
Various diets restrict carbohydrate intake. The ketogenic diet is very high in fat, low in protein, and very low in carbohydrates. The Atkins diet is high in fat, high in protein, and very low in carbohydrates.
The “paleo diet” (hunter-gatherer diet) is high in fat, high in protein, and low in carbohydrates.
Fats and proteins are digested more slowly than carbohydrates, so they are more filling.
Also, most diets (including the three already mentioned) recommend eating foods that are lower in calories (more fiber and higher water content – a pound of broccoli contains fewer calories than a pound of grains).
Finally, carbohydrates are involved in the synthesis of serotonin, which can cause cravings in some obese people.
Therefore, people on low-carb diets lose weight because they naturally eat less and avoid the big binges caused by carbohydrate cravings.
People on very low carbohydrate diets can also lose weight very quickly in the short term because the depletion of their glycogen stores leads to the excretion of bound water.
That explains why two trials found that people on a low-carb diet lost more weight than people on a low-fat diet after 6 months but not 12.
Eating your macronutrients together (balanced diet) or separately (decoupled diet, also known as “food combining”) makes no difference to weight or fat loss.
Since prolonged fasting can increase calorie expenditure, diets that manipulate fasting (intermittent fasting, alternate fasting) may have some benefits on the “calorie out” side of things.
However, even here, the weight lost is mainly due to the fact that you control your eating: it is much more difficult to overeat in 8 hours than in 16.
