Every year U.S. News and World Report gathers dozens of nutrition experts and has them rank the best diets. This year, Whole30 finished dead last—well behind Jenny Craig, WeightWatchers, and even Atkins.

To say we were surprised is an understatement. We partnered with the program to launch Greatist Groups, our way of connecting readers with small teams of people who are also looking to crush Whole30 but could use some added tips and support. We don’t stand to profit from this partnership: We did it because we’re huge believers in Whole30.

Is Whole30 a Diet?

Calling the program a diet is complicated. Technically, everyone is on a diet. It’s simply a collection of all the stuff you usually eat. But most people think of a diet as something you go on when you’re trying to lose weight.

That’s the first problem: Whole30 isn’t really about weight loss. Yes, we know many people lose weight while sticking to the program, but Whole30 bills itself as a nutritional reset that changes your relationship with food. It’s about changing the way you feel. Maybe you’re bloated, or your skin won’t stop breaking out, or you’re tired all the time.

It’s much more helpful to think of the program as an elimination diet. And boy oh boy are you expected to cut out a lot! The short list: no sugar, alcohol, grains, legumes, or dairy—and no weighing yourself.

Most nutritionists don’t recommend cutting out entire food groups (unless you’re allergic). It’s not sustainable. But that’s where Whole30 differs from other popular diets, like Paleo. You do the program for 30 days and then start reintroducing the foods you cut out. If they make you bloated, mess with your skin, or leave you feeling groggy, try to keep those foods at a minimum.

Whole30 Is Difficult

There’s no sugarcoating it (pun kind of intended). Whole30 is hard—really hard. For most people, the first week is full-on withdrawal. You crave sweets, you dream of beautiful baguettes, and you’re willing to do pretty much anything to get your hands on a glass of wine.

The program isn’t for everyone. There’s a long list of no-nos, and eating out is nearly impossible. (It is easier when you’re doing it with a group of people to share the highs and lows—shameless self-promotion, we know.) The upside? You’re only eating whole foods. Really, what could be better? There are no shakes, no synthetic protein powder, no microwaveable dinners. It’s the stuff your grandparents ate (without a glass of milk to wash it all down, of course).

For most people, you’ll be eating more protein than you’re used to. It’s not a no-holds-barred approach like Atkins (and ironically, Atkins fared better in the U.S. News rankings). The founders recommend eating protein three times per day with each serving being about the size of the palm of your hand. While it’s higher than the U.S. Dietary Guidelines, it does fall in line with what many nutritionists suggest.

The Results

Hopefully, at the end of the month, you start to feel more alive (the energy boost is insane), you change how you think about eating and snacking, and you probably realize the reason you get hangry at 3 p.m. is more mental than physical hunger.

In the end, it’s only 30 days. Melissa Hartwig, one of the program’s founders, is known for saying, “It’s Whole30, not Whole365.” In the dieting world, that’s a radical idea. Most other commercial diets claim to be long-term solutions. The longer you stick with it, the more money they rake in. And even if you fall off the bandwagon, they know you’ll come crawling back when you want to shed a few pounds in the future. It’s a vicious cycle.

While Whole30 is extreme, it teaches you more about your body (and what it needs to stay nourished) than any other diet we’ve tried. And that’s something that lasts well beyond the 30 days.