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.

Similar to the CICO diet, the Body Reset has gained popularity via social media, and there isn’t any definitive research that suggests the approach is safe and effective. Celebrity trainer Harley Pasternak created the plan, which is essentially a three-phase liquid diet comprised of smoothies and moderate exercise. While U.S. News notes you may lose weight on the diet, it may be tough to stick with, and isn’t safe for people with diabetes and heart disease. (38)
Very few diet plans outlive temporary fads and trends, and WW is definitely one of them. The diet company formerly known as Weight Watchers has kept up with the times by reinventing and rebranding itself as WW, which stands for “Weight Loss & Wellness.”  While the company’s diet approach is still based on the Smart Points food-tracking system, it has recently incorporated meditations, audio workouts, food logging, Zero-Point foods, a redesigned app, and online support for a more holistic approach to dieting.
If you’re only getting a minimal amount of sleep each night, that leaves more time for you to snack and make otherwise unhealthy decisions that could affect your weight loss. Although it will vary from person to person on how much sleep you actually need to be most effective (and therefore make progress toward your weight loss goals), the ideal number is typically 7 or 8 hours, says Dr. Cheskin.
Also some research shows that the human body is primed to consume most of its calories during daylight hours. But the lifestyle is problematic for many: Because family meals and dinners with friends often are scheduled for after sunset, "people who try to stop eating after 7pm can’t do it every day for the rest of their lives," says Dr. Seltzer, who supports an alternative strategy: Eating a hearty meal at your regular dinnertime.
Popularized by the documentary Forks Over Knives, the Ornish diet is a low-fat, plant-based diet plan based on whole grains, vegetables, fruits, and legumes. It's based on a lacto-ovo style of vegetarianism, allowing only egg whites and nonfat dairy products. It's packed with vitamins, fiber, and lots of filling plants to keep you satiated. Some studies have shown it can reverse heart disease and have beneficial effects on other chronic health conditions. (BTW, there is a difference between a vegan diet and a plant-based diet.)
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