For example, when it comes to hormones, ghrelin makes you hungry, leptin and other hormones keep you feeling full, Nadolsky says. Thyroid, cortisol, insulin, testosterone, and estrogen all influence how you metabolize and store energy. Meanwhile, genetics have a large influence on both basal metabolic rate (how many calories you burn just to live) and hormone health. While all of these things are impacted by our diet, they’re not only controlled by the way we eat. And, in fact, while sleep, stress management, and, when needed, medication can help regulate other hormone levels such as estrogen and thyroid, our hormones and other physiological processes are often out of our control. And by the way, being able to impact our hormone levels and metabolism with our diet doesn’t always work out in favor of weight loss. As a 2016 review notes, one of the reasons weight loss by way of caloric restriction isn’t efficacious is because “this strategy is countered by the body’s natural physiological response to negative energy balance.” In other words: The body fights back against caloric restriction.
When Johns Hopkins researchers compared the effects on the heart of losing weight through a low-carbohydrate diet versus a low-fat diet for six months—each containing the same amount of calories—those on a low-carb diet lost an average of 10 pounds more than those on a low-fat diet—28.9 pounds versus 18.7 pounds. An extra benefit of the low-carb diet is that it produced a higher quality of weight loss, Stewart says. With weight loss, fat is reduced, but there is also often a loss of lean tissue (muscle), which is not desirable. On both diets, there was a loss of about 2 to 3 pounds of good lean tissue along with the fat, which means that the fat loss percentage was much higher on the low-carb diet.
While many people turn to artificial sweeteners in a misguided attempt to whittle their waistlines, those fake sugars are likely to have the opposite effect. According to Yale researchers, artificial sweeteners are actually linked with an increased risk of abdominal obesity and weight gain, possibly because they can trigger cravings for the real stuff and spike insulin levels in a similar fashion to real sugar.
Here's something else most people probably don't know: Fidgeting is good for you. It's considered a nonexercise physical activity, and it's an important way to burn energy. You get more health benefits if, in addition to exercising, you are a more fidgety, more active person the rest of the day. This means gesturing while you're talking, tapping your foot, just moving around.