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What Is the 20/21 Diet?

Updated: Aug 6, 2021


What's the best diet plan for weight loss? Not all popular plans give safe, long-term results. Knowing what a sustainable plan is can help you choose a good one.

The 20/21 Diet is an interesting diet based on the concept of “power foods” that purportedly take a lot of energy to digest. It’s meant to help people lose weight, but it could wind up backfiring. In this article, learn everything there is to know about the 20/21 Diet, from pros and cons to everything you can & can’t eat, and a healthy diet plan for weight loss.

Through this blog, we'll make you aware of easy diet plans to lose weight.

How It Works

The 20/21 diet is based on the concept of thermogenic. When something is thermogenic, it means it has a tendency to produce heat. In regard to weight loss, this concept suggests that certain foods make your body work extra hard to digest them and that energy is released as heat (also known as the thermic effect of food) The more energy your body burns while digesting food, the fewer net calories you absorb from that food.

To that end, the 20/21 diet emphasizes 20 “power foods” that supposedly take up a lot of energy to digest. Those foods are coconut oil, green tea, mustard, olive oil, almonds, apples, chickpeas, dried plums, prunes, leafy greens, lentils, peanut butter, pistachios, raisins, yogurt, eggs, cod, rye, tofu, and whey powder.

This theory sounds nice, but there isn’t any conclusive scientific evidence to support the assertion that all 20 foods require more energy to digest than other foods. The green powder seems to be the only food on the list with any conclusive thermogenic data behind it. Some research has, in fact, found green tea to be a metabolism booster,1 but other research contradicts those findings.2

Some of these foods, such as apples and leafy greens, might help you lose weight because they pack a lot of nutrition with few calories. Other foods on the list are high in calories (e.g., peanut butter, dried fruit, pistachios) and can contribute to weight gain if you aren’t careful about portions.

What to Eat

Compliant Foods

  • 20/21 “power foods”

  • Animal proteins

  • Dairy products

  • Starchy and non-starchy vegetables

  • Fruit and dried fruit

  • Fish and seafood

  • Healthy fats

Non-Compliant Foods

  • Refined carbohydrates and sugars

  • “Junk” food

  • Fast food

20/21 “power foods”: This group includes the core foods on the 20/21 diet, which are thought to burn a lot of energy during digestion, according to McGraw.

Animal proteins: You can add proteins such as chicken breasts and lean ground beef into your diet after the first phase.

Dairy products: Yogurt is one of the 20/21 power foods, and you can also eat cheese and drink milk later in the program if you want to.

Starchy and non-starchy vegetables: Some veggies are included in the 20/21 power foods, and you can eat all the vegetables you like in the later phases of the plan.

Fruit and dried fruit: The 20/21 power food group includes some fruit and dried fruit, and you can include additional varieties after phase one of the diet.

Fish and seafood: McGraw encourages consuming fish and seafood throughout the entire diet plan. Cod is one of the 20/21 power foods. Fish and seafood provide ample vitamins, minerals, and healthy fatty acids.

Healthy fats: Nuts and seeds, avocados, olives, and cooking oils are encouraged on the 20/21 diet.

Refined carbohydrates and sugars: While not completely off-limits in the later phases of the diet plan, McGraw recommends avoiding foods with simple carbs and sugars.

“Junk” food: McGraw advises refraining from foods that trigger “free-for-all eating,” such as processed snacks that come in wrappers, bags, and boxes.

Fast food: Part of McGraw’s philosophy with the 20/21 diet is avoiding old habits that caused you to gain weight, such as frequenting your favorite fast-food restaurants.

Recommended Timing

The 20/21 diet consists of four distinct phases. During all phases, you’re supposed to eat four meals, four hours apart.

Phase 1: The Five-Day Boost

During phase one of the 20/21 diet, you only eat the 20 foods designated as power foods.

Phase 2: The Five-Day Sustain

During phase two of the 20/21 diet, you start adding in foods outside of the 20 power foods, but each meal or snack must contain at least two of the 20 power foods.

Phase 3: The 20-Day Attain

Phase three is significantly longer than phases one and two, and things become more structured. Each meal must contain at least one of the 20 power foods. You’re also allowed two “sensible splurges” of any food you enjoy per week, but only if they stay under 100 calories.

Phase 4: Management

When you get to phase four, it’s all about maintaining your weight loss and new eating habits. This article focuses on daily lifestyle tips and encourages you to not allow a busy lifestyle to get in the way of your nutrition.

If you don’t meet your goal weight by the end of phase three, you’re supposed to start over and keep repeating phases one through three until you achieve your goal weight.

Resources and Tips

For the best results on the 20/21 diet plan, consider buying McGraw’s book. The book details the specifics of the plan and includes sections on managing your mindset during weight loss.


While the first two phases of the 20/21 diet don’t allow for much modification, the diet gets more flexible once you enter phases three and four. No foods are truly off-limits at that point, so you can modify the 20/21 diet to meet your dietary preferences, whether you follow a vegan, vegetarian, Paleo, low-carb, or other eating plans.

People who eat a vegan diet may struggle with the 20/21 diet, especially in the first two phases, because the 20/21 diet encourages the consumption of yogurt, eggs, and whey powder. While there are still plenty of other foods to choose from, vegan dieters will have to modify recipes that include animal products.


  • Includes a Variety of Foods

  • Encourages Exercise

  • Encourages Hydration

  • Accounts for Mental Health


  • One-Size-Fits-All Approach

  • Could Lead to Disordered Eating Habits

  • Too Structured for Some

  • Relies on Questionable Approaches to Weight Loss


Includes a Variety of Foods

While the first phase of the 20/21 diet limits you to 20 foods, your options open up after those first five days. The 20/21 diet encourages people to consume a variety of healthy foods, from animal proteins to starches to vegetables. McGraw doesn’t completely discourage treats and processed foods, but he does stipulate that your “sensible splurges” should be few and far between (no more than twice a week) and limited in calories.

Encourages Exercise

The 20/21 diet provides exercise recommendations on top of nutritional recommendations, which is something that not all diet plans help with. In particular, McGraw suggests getting three to four hours of moderate-intensity exercise per week and two to three hours of vigorous exercise. If you meet both minimums, you’ll engage in at least five hours of exercise per week, and up to seven if you meet the maximums.

Encourages Hydration

Additionally, the 20/21 diet provides hydration recommendations. While everyone needs to drink different amounts of water based on their body size, activity level, medical conditions, and other factors, aiming for eight to 10 glasses (like suggested in the 20/21 diet) makes for a good goal.

Accounts for Mental Health

Though McGraw is not a registered dietitian, he does have experience helping his clients manage their weight. McGraw uses his knowledge of mindset, motivation, and other mental factors to provide weight loss tips. Your mental health can greatly affect your ability to lose or maintain your weight, and weight loss is rarely a black-and-white situation of “calories in, calories out.” McGraw touches on mental health as it relates to weight loss is a nice touch and a learning opportunity.


One-Size-Fits-All Approach

Nutrition experts agree that weight loss is a highly individual process. Successful weight loss requires customization to a person’s health status, activity level, current lifestyle, medical conditions, past eating habits (e.g., disordered thing), and much more. Plans like the 20/21 diet assume that everyone can lose weight following the same plan, which just isn’t true.

Could Lead to Disordered Eating Habits

Any diet can lead to disordered eating habits and a strained relationship with food. The 20/21 diet is no different. If you have a history of disordered eating, cutting out foods and restricting your eating schedule may lead to binge-eating behavior or other unhealthy eating habits.

Too Structured for Some

The whole “eat every four hours” thing could be a bit too much for some people. With busy lives, it’s hard to keep track of exactly when we eat. Plus, this strategy completely neglec