What is Whole30? Dietitians weigh in on what some call the 'worst' diet (2024)

You’ve likely heard of Whole30 or maybe even tried it yourself. The diet involves eliminating sugar, dairy, grains, alcohol and other major food groups for 30 days — no calorie counting involved.

According to the Whole30 website, the program is designed to be a “short-term reset” which promises a variety of benefits, from weight loss to high energy levels. Since it came on the scene in 2009, Whole30 has garnered millions of followers and become a popular fad diet, especially around New Years resolution time. The diet is intense and restrictive — many people call it the Whole30 “challenge.”

However, Whole30 has never ranked high among top diets by experts. It didn't even make the list of overall best diets in 2023 from U.S. News & World Report.

Despite having many critics, the 30-day elimination diet remains popular — likely thanks to social media. Proponents of the diet have flocked to Facebook and Instagram to share their Whole30 recipes, progress and results. There are over 4.4 million posts on Instagram using the hashtag #whole30 with countless photos of delicious-looking meals.

So how does the Whole30 diet work and is it actually healthy? Here’s what experts say.

What is Whole30?

Whole30 is basically an elimination diet — you cut out certain foods, namely processed ones. By following the Whole30 diet rules and not eating foods that are likely to contain common allergens or trigger inflammation, you can see how your body responds. That means no cheating — you’re expected to follow the program to the letter for 30 days.

The idea is that by cutting these foods out, you'll learn which of them haven't been working for your body. After 30 days, you systematically reintroduce the forbidden food groups and pay attention to how they make you feel. In a way, you're using your body as a laboratory and testing what causes you to have a reaction and what doesn't.

But that science-y sounding strategy doesn't mean that Whole30 isn't a diet. It definitely is.

“Whole30 is a diet in the traditional sense — it tells you what you can and can’t eat,” Karen Ansel, a New York-based registered dietitian and author of “Healing Superfoods for Anti-Aging,” tells TODAY.

Unlike some diets, though, weight loss is not the goal of Whole30. You can eat what you like from the allowed foods — you don’t have to count calories. While people may turn to Whole30 to lose weight, that's not what it was designed for. In fact, you’re supposed to stay away from the scale while you’re following Whole30.

The 2 phases of the Whole30 diet

Whole30 has two distinct phases:

• The elimination phase: The elimination phase of Whole30 is 30 days long. During this time, you are only allowed to eat whole, unprocessed foods.
• The reintroduction phase: The reintroduction phase of Whole30 is 10 days long and follows the elimination phase. During the reintroduction period, you gradually reintroduce some of the forbidden foods back into your diet.

Whole30 Rules

Whole30 meals are built around one to two palm-sized protein sources. The rest of your plate is filled with vegetables. Healthy fats are included in recommended amounts. You can include fruit occasionally. On Whole30, snacks are allowed, but not recommended — waiting three to five hours between meals is preferred. You can find information, resources, support and easy Whole30 recipes at Whole30.com.

Whole30 food list

On the Whole30 diet, you eat a whole-food-focused diet. Whole30 recipes include Whole30-approved foods like:

• Meat and seafood
• Eggs
• Veggies (except corn and lima beans)
• Fruits
• Natural fats (like coconut oil and avocado oil)
• Seeds and nuts
• Herbs and spices
• Coffee and tea
• Juices
• Kombucha

Whole30 recipes:

• Breakfast: Roasted potato and kale hash with eggs
• Lunch: BLT salad
• Dinner: Shrimp stir-fry over cauliflower grits

What you can't eat on the Whole30 diet

The Whole30 meal plan eliminates foods that could trigger allergies, reactions or inflammation. That means these foods won’t make it onto your Whole30 shopping list:

• Added sugar and artificial sweeteners
• Alcohol
• Grains
• Most legumes, including beans, peanuts and soy
• Dairy
• Carrageenan, MSG or sulfites
• Baked goods or junk food, even if they are made with approved ingredients

Is Whole30 actually healthy?

Samantha Cassetty, a registered dietitian based in New York City and the co-author of “Sugar Shock,” tells TODAY that there’s no scientific evidence to support the health claims made by the Whole30 diet, and it wasn't designed by a credentialed expert. In fact, there’s little independent research that specifically evaluates the Whole30 diet. Anecdotally, people who have tried it share testimonials that it has helped them with a wide range of health conditions.

“I know people who have tried it, and I don’t discount anybody’s personal experience,” Cassetty says. The diet can make you aware of how much processed food or added sugar you’re consuming, or how you’re interacting with alcohol. “When you come off it you can be more thoughtful about those types of things,” Cassetty says.

But the diet eliminates a lot of foods that are generally considered healthy. “My concern with Whole30 is that there’s a long list of what you cannot have, and that includes foods that are linked to good health in many ways,” Ansel says. “When people are cutting out entire food groups, that’s always a big red flag.”

Ansel is especially concerned that the diet doesn’t allow:

• Grains, since whole, minimally processed grains are good for our guts
• Beans and legumes, which are good sources of fiber
• Dairy, which contains calcium to support bone health

Ansel also worries that a 30-day diet may set you up for yo-yo dieting. Cassetty agrees: “Phase diets get such a bad rap because people put their lives on pause to do something for a short period, then go back to eating what they used to before. Whatever benefits they experienced are immediately canceled out the minute they resume their former eating patterns.”

Is the Whole30 diet effective long-term?

Whole30 isn’t intended to be a long-term diet. By evaluating how you feel before and after Whole30, you may become more mindful about your eating habits and to learn to identify foods that are troublesome for you.

Since there is no clinical research on Whole30, it remains to be seen whether this diet will hold up in the long-term. Talk with your doctor before starting the Whole30 diet or any other diet — your doctor can recommend the best eating plan for you, based on your health needs.

Is Whole30 a good choice for you?

“I think it’s overly restrictive,” Cassetty says. If you want to try a new way of eating, she recommends making small, sustainable, healthy changes like cooking at home more often and eating more vegetables.

You might be considering the Whole30 diet if you suspect the food you eat is affecting how you feel. There are times when an elimination diet is appropriate, Cassetty says. But an elimination diet should be done under the guidance of a dietitian, for a specific reason. “You might not need to eliminate all of the foods that are eliminated on Whole30. If you’re having some problem, the goal is to eliminate as few foods as possible,” Cassetty says.

“Foods like tofu, whole grains and pulses can absolutely fit into a long-term healthy eating plan,” Cassetty says. She pointed to the DASH diet, Mediterranean diet and MIND diet as good long-term options. “The people in the Blue Zones, who are living the longest disease-free lives, aren’t doing the Whole30.”

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