Before you could say “pass the bone broth,” this buzzy eating plan took off in a serious way throughout 2015. The highly restrictive diet—which requires followers to eschew grains, legumes, dairy, and sugar in favor of a diet rich in meat and veggies—is followed by celebrities like Uma Thurman, Jessica Biel, and Megan Fox. Basically you have to cut out all the good stuff to be paleo, but devotees believe strongly that this lack of carbs helped spur the dramatic increase in brain size that humans experienced over the past 800,000 years. So, obviously, it must be good for you.

Well, that was the thought; however, the mood has been shifting lately, with research pointing out flaws in the program—like the study that proves carbs were actually readily available to cavemen, in the form of tubers, roots, seeds, and certain fruits. In fact, researchers even found that it’s likely that eating carbs was the reason our brains developed so rapidly, which fully debunks the paleo theory.

Between the low calorie intake and intermittent fasting, the military diet seems kind of high-maintenance, but it does promise major results. Zuckerbot shed some light on how it works: “The military diet plan is a three-day diet that claims you can lose up to 10 pounds in one week. The diet includes a strict three-day plan with no guidance for what to eat during the other four days on the plan. The program is safe; however, it is not effective for long-term, sustainable results.”

Also, as you’d assume from a diet that promotes fasting, you’re going to feel really hungry if you try to follow the military style of eating. As with most calorie-restrictive meal plans, any results won’t last long: “The three-day program is not flexible, and because it lacks fiber, the participants will feel hungry and unsatisfied. It also does not offer any long-term solutions,” Zuckerbrot explained. 

You’ve probably heard of this style of eating before—it’s essentially the two-week introductory phase to the popular Atkins Diet, a method that restricts carbs. “The Atkins induction diet starts dieters on a low-carb diet. This induction phase is only designed to be followed for two weeks to jump-start weight loss.”

While it’s not harmful, cutting carbohydrates might not be the best way to lose weight: “It is safe, however, not effective for weight loss. Carbohydrates, especially high-fiber carbohydrates, help boost metabolism and burn fat. Without any high-fiber carbs, the dieter will feel hungry and deprived. Also, the foods are limited and include a lot of high-fat, calorically dense foods that can be counterproductive to weight loss,” Zuckerbrot explained.

The moral of the story here is that no crash diet is going to keep you looking and feeling fit and healthy in the long term. You already know this, but Zuckerbrot suggests avoiding any diet that’s short-term and highly restrictive—or risk gaining the weight back really quickly. “Followers will gain back any weight they may have lost once they resume a more normal eating pattern. Cutting out entire food groups or isolating intake on particular days of the week will not provide lasting results because this type of eating pattern is not sustainable,” she said.

Essentially, not only will you feel hungry 24/7 on some of these buzzy fad diets, but you could lose lean muscle mass, something that you need to burn fat: “Muscles burn more calories than fat. Losing muscle mass is counterproductive for those looking to burn calories and lose weight. Quite honestly, I find Google’s most searched diets bizarre. They contribute to the fad-diet ‘noise’ that impedes efforts at successful weight loss.”

Instead, she suggests sticking to a diet grounded in whole, unprocessed foods that fit with your lifestyle.