When we began our research on Nutrisystem, the first thing that stood out to us was the variety of  plans they offer. In total, there are nine different options, including plans for diabetics, vegetarians, and even special diets for men (a rarity in the diet industry). Also, most of their plans are highly customizable, so if you don’t like their recommendations you can customize your meal plan from chef-created menu items including staples like chicken masala, cheesesteak pizza, muffins, burgers, popcorn, and lots more.

"What I don't like about any commercial diet is that the focus is not on your actual food choices," Hogan said. "It's about calories or points or numbers, and that really takes away from your ability to be in tune with your hunger cues and your fullness cues and what you're really craving. If we become more in tune with those things, we naturally consume how much the body needs. Paying too much attention to numbers takes away from that."


Right now, this is the trendiest of all diet theories. It prioritizes the consumption of foods high in protein and fat while limiting the number of carbs per day to less than 20%. This means abstaining from grains, starchy vegetables, and fruits, and filling up on protein and fat. The most famous of all low-carb plans is the Keto Diet, an approach based on the metabolic process of ketosis, which happens when you restrict your carb intake to less than 0.7 grams per day and your body starts using fat, and not carbs, as its main fuel. 
The one thing that is sure to make you lose weight is this simple equation: CICO, short for “Calories In, Calories Out.” In short, it means: a) if you eat more calories than your body spends, you’ll gain weight; b) if you eat less calories than you spend, you’ll lose weight. In spite of all their differences, all diet plans that aim to help you lose weight must adhere to this seemingly simple equation. However, most experts agree that, by itself, CICO is an incomplete and flawed approach due mainly to its focus on quantity over quality, and the fact that it doesn't take nutrients into account.
“A lot of people think the foundation of a paleo diet is high-fat meat, but I suggest that it’s vegetables,” says Hultin. The concept is to eat only foods — including meat, fish, poultry, eggs, fruits, and vegetables — that would have been available to our Paleolithic ancestors. This means grains, dairy, legumes, added sugar, and salt are all no-no’s.

With this eating style, you’re looking at a lot of menu planning and preparation. A review published in August 2017 in Nutrients suggests the diet could lead to weight loss, but the Academy of Nutrition and Dietetics warns the plan could also cause certain nutrient deficiencies, such as in calcium and vitamin D. (3,4) And, therefore, according to an article published in the January–February 2016 issue of the Royal Australian College of General Practitioners, anyone at risk for osteoporosis should avoid it. (5)
After thoroughly researching the most popular and expert-recommended diet plans, we determined that all the diet plans to be included in our "Best of" list should meet the criteria stated below. However, there is one very important factor that, though essential to a person’s decision on whether or not to begin a diet, we could not review first hand: that factor is taste. 
If you like eating meat and want to lose weight, you might be tempted to try this recent extreme diet fad that proponents have made some pretty outrageous claims about. One: that eating nothing but meat can cure you of autoimmune diseases. The problem is that there’s no good research to support that notion, or any other health claim, for that matter. Indeed, omitting foods known to be good for you — fruits and veggies among them — can lead to a bunch of unwanted side effects, including constipation and potentially dangerous nutrient deficiencies. Still, since you’re cutting out so many food groups, there’s a decent chance you’ll lose weight, experts say. Regardless of any possible benefits you might see, this restrictive approach is definitely one you’ll want to ask your doc about before you even consider diving in.
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