Most people have been taught that losing weight is a matter of simple math. Cut calories—specifically 3,500 calories, and you'll lose a pound. But as it turns out, experts are learning that this decades-old strategy is actually pretty misguided. "This idea of 'a calorie in and a calorie out' when it comes to weight loss is not only outdated, it's just wrong," says Dr. Fatima Cody Stanford, an obesity specialist at Harvard Medical School. The truth is that even careful calorie calculations don't always yield(产生) uniform results.
How your body burns calories depends on a number of factors. Three factors affect how your body processes calories.
Your gut microbiome (肠道微生物). Trillions of organisms live in your gut, and the important types may influence how many calories your body absorbs from food. This may occur because some types of organisms are able to break down and use more calories from certain foods than other types of organisms. Researchers have found that people who are naturally thin have different types of organisms living inside them than those who are overweight.
Your metabolism (新陈代谢). Each body has a "set point" that governs weight, says Dr. Stanford. This set point reflects several factors, including your genes, your environment, and your behaviors. A region at the base of your brain stands guard to keep your body weight from dipping below that set point—which is not really a bonus if you're trying to lose weight.
The type of food you eat. Your food choices may also influence your calorie intake, and not just because of their specific calorie content. One 2019 study published in Cell Metabolism found that eating processed foods seems to spur people to eat more calories compared with eating unprocessed foods.
If counting calories isn't a dependable way to manage your weight, what can you do toshedextra pounds? Dr.
Stanford recommends the following.
Focus on diet quality. When planning your meals, focus on choosing unprocessed foods, including lean meats, whole grains, and lots of fruits and vegetables in their natural form.
Exercise regularly. Aim to get at least 150 minutes of moderate-intensity exercise each week. Moderate exercise is done at a level where you can talk, but not sing.
Consult a professional. "A lot of people believe it's a moral failing if they are unable to lose weight," says Dr. Stanford. But it's not. As with other medical conditions, many people will need help from a doctor. Successful weight loss may require more than just diet and exercise. "Only 2% of people who meet the criteria for the use of anti-obesity medications actually get them. This means that 98% of people who could be treated aren't," she says, "Don't be afraid to seek help if you need it."
