Consequently, researchers have widely discredited the hCG diet, which involves using hCG injections, pellets, sprays, or drops, and consuming as few as 500 calories daily. The diet is problematic not only because there’s a lack of research on hCG supplements, but also because the calorie requirement is dangerously low, potentially leading to nutrient deficiencies, fatigue, hormone imbalances, blood clots, and other issues. Thus, most experts agree the hCG diet is not safe for anyone, the Mayo Clinic notes. (35)
The idea is that the fasting induces mild stress to the cells in your body, helping them become better at coping with such stress and possibly helping your body grow stronger. The verdict is still out regarding the diet’s long-term effectiveness with weight loss, according to a review of preliminary animal research published in January 2017 in Behavioral Sciences. (17)
The fad military diet consists of low-calorie, odd food pairings such as bun-less hot dogs with banana, carrots, and broccoli. “Any diet like the military diet that severely limits the amount of calories you consume or eliminates one or more entire food groups puts any individual at risk for nutrient deficiencies,” says Kyle. “This can be more harmful than holding onto those 10 extra lb you’re trying to lose.” (32)
Like protein, fiber slows the rate at which your body plows through carb calories so you feel full for longer and maintain steadier blood sugar levels, one reason why research consistently links fiber intake to weight loss. That means fibrous whole grain bread tends to be a better choice than white bread and also explains why fruits, which contain fiber and valuable vitamins in addition to sugar, beat straight-up candy every time.
Research also finds that drinking frequently—even if it’s a moderate amount—can set you up for excess pudge. Not only do the beverages themselves contain unnecessary calories, but once you start sipping too much, your inhibition also plummets, according to one 2016 study. The result? You’ll have a hard time resisting that late-night slice of pizza. So if you're going to imbibe, be sure to stick to one drink per day for women and up to two drinks for men.
Based on the concept of caloric density, which states that some foods have few calories in proportion to their size (say, a lettuce), while others have lots of calories packed in small portions (a regular chocolate chip cookie comes to mind), Volumetrics divides foods into 4 categories based on their calorie/volume ratio, and is perfect for people looking to binge on some foods while still shedding pounds. However, as with the calorie counting approach, Volumetrics does not take into account the quality of the calories, prioritizing quantity instead. The app Noom and Weight Watchers (both reviewed above) share similarities with this diet theory.