Eat less, exercise more. Calories in, calories out.
These phrases are probably familiar to you if you have tried to lose weight. This is because these concepts make up the traditional explanation for why people gain weight and the most common method of losing weight.
More and more research suggests that gaining and losing weight might involve more that the simple math of counting calories. It may be that the source of the calories matters as much as the total amount that you eat.
However, this doesn’t mean that you can ignore the calories you eat and expend through exercise and other activity. While it may be true that the quality of the food we eat is important, calories still count.
A recent article in the Journal of the American Medical Association proposes an alternative to the classic model of how weight gain occurs. Traditionally, an imbalance between calories in and calories out causes obesity. According to this model, eating too much and not being active enough results in increased fat storage.
The new model suggests that diet quality, especially the type and amount of carbohydrates, combined with genetics and lifestyle factors including getting enough sleep and excessive stress leads to fat accumulation. The excess fat alters levels of hormones and other factors that stimulate hunger and inhibit energy expenditure, including physical activity.
In the new model, increasing fat mass comes first and excessive food intake and inadequate activity follows. The end result is the same, though: a small increase in body fat turns into obesity.
This seems to suggest that carbohydrate intake, especially from refined grains and sugars, is the main culprit. This is good news for people who follow and promote low-carb diets! It also gives the impression that exercise isn’t as important as previously believed.
But a closer look at the new model shows that obesity—storage of excessive body fat—really is the result of too many calories in and too few calories out. The difference is that the eating and activity behaviors is driven by other factors.
The fact of the matter is that diet quality, genetics, and factors such as stress and sleep do play a role weight gain. Changes in hormones, sugars, and fats in the blood are real and powerful physiological signals that certainly contribute to obesity.
But so do changes in how much we eat and how active we are. It would be wrong to disregard these behavioral factors and the important role they play not only in body weight regulation, but in health in general.
Furthermore, the traditional calories in, calories out model of weight gain leads to a sensible treatment for obesity: Eat less, exercise more. Even though these simple recommendations can be challenging to implement, certainly in the long term, people who follow this advice do lose weight.
Even in the new model, calories in must be greater than calories out to lead to the significant fat gain that characterizes obesity. Additionally, the focus on the food quality is also consistent with this idea. People who get more of their calories from refined grains and sugars tend to consume more total calories.
As of now, the only treatments we have for obesity focus on changing energy intake and energy expenditure. This almost always involves altering eating and activity behaviors and frequently includes other lifestyle changes including stress management and getting enough sleep.
Given this new model of obesity, the best way to lose or maintain weight is not new at all: Eat less, move more, chill out!