Flat Belly Diet Overview


Weight Loss Short-term
Weight Loss Long-term
Easy to Follow
For Diabetes
For Heart Health

Scores are based on experts' reviews

Pros & Cons

  • Tasty menu recipes
  • Abundant guidance and resources
  • Skimpy evidence that “good” fats are magic bullet
  • Fewer days of menus than other plans

Do's & Don'ts

Don’t: Eat much saturated fat See more Do's & Don'ts




Resembles these U.S. News-rated diets:

Abs Diet

The aim:

Weight loss.

The claim:

You’ll drop up to 15 pounds in 32 days and lose several inches of belly fat.

The theory:

Monounsaturated fatty acids, or MUFAs, target and destroy belly fat while promoting fullness and preventing overeating, according to the diet’s creators, former Prevention magazine editor Liz Vaccariello and registered dietitian Cynthia Sass. These plant-based fats are found in foods like nuts, seeds, chocolate, avocados, and olive oil—and the Flat Belly Diet (Rodale, 2008) calls for a precisely specified serving at every meal and snack. Unlike saturated fats, which harden and clog the arteries, MUFAs keep blood vessels soft and pliable after digestion. In addition to emphasizing these healthy fats, the Flat Belly Diet is modeled after a Mediterranean eating approach. The key ingredients—fruits, veggies, legumes, whole grains, olive oil, and fish—are thought to help keep weight off.

How does the Flat Belly Diet work?

One MUFA serving with every meal and daily intake of 1,600 calories, although dieters can tailor the plan to their age, gender, and activity level. Fruits and veggies, whole grains, nuts, beans, seeds, and lean protein are emphasized. There are two parts: a four-day “anti-bloat” jumpstart, and a four-week eating plan. The book includes extensive meal plans, recipes, and grocery lists, minimizing guesswork and planning. Though both men and women can follow Flat Belly, it’s geared toward a female audience—and women will likely favor the style of the book. There is, however, a separate book for men; the plans are nearly identical, but men get more calories.

The initial four-day anti-bloat regimen is the most restrictive part of the program, capping daily calories at 1,200. It’s touted as a clean and simple way of eating that eliminates ingredients that promote unnecessary fluid retention and gas. Each day, you’ll have four 300-calorie meals that adhere to a rigid list of acceptable food and drink. That means lots of baby carrots, cucumbers, grape tomatoes, skim milk, extra-virgin olive oil, sunflower seeds, applesauce, chicken breast, organic deli roast turkey, tilapia, and fresh or dried basil. You’ll also have 2 daily liters of homemade “Sassy Water,” which the authors claim “helps calm and soothe your GI tract.” It contains ingredients like ginger, cucumber, and mint leaves. Off limits: alcohol, coffee, tea, hot cocoa, and acidic fruit juices, chewing gum, fatty foods, salt, broccoli and Brussels sprouts, and anything seasoned with barbecue sauce, horseradish, garlic, chili pepper, black pepper, or other spices.

Then comes the four-week eating plan. You’ll get three 400-calorie meals and one 400-calorie snack each day, and never go more than four hours without eating. Each meal is designed to include the right amount of one MUFA, such as 1 cup of soybeans, ¼ cup of semisweet chocolate chips, or 2 tablespoons of olive tapenade. (Other MUFA options include almond butter, pesto sauce, tahini, and sunflower seeds.) You’ll consume no more than 4 grams of saturated fat per meal, keep salt below 2,300 milligrams a day to prevent water retention, eliminate trans fat, and avoid artificial sweeteners, flavorings, and preservatives.

Flat Belly meals are built around MUFAs, lean protein, a choice of whole grains or fruit, and (for lunch and dinner) vegetables. Although sample menus are provided, you’re free to create your own meals. Start by selecting a MUFA and use the book to determine how many calories are left to work with. If your MUFA choice is nuts, for example, you’ll have about 300 calories remaining. Your meal might consist of 3 ounces of lean protein; 2 cups of raw or steamed veggies; and either ½ a cup of cooked whole grains, 1 whole-grain bread serving, or 1 cup of fruit.

A spinoff, Flat Belly Diet! For Men, is broken into a four-day “flat abs kickstart” and a monthlong “MUFA meal plan.”

Will you lose weight?

The only evidence suggesting that you might comes from small, short studies. The Mediterranean Diet, on which the Flat Belly Diet is loosely modeled, seems to promote weight loss or a lower likelihood of being overweight or obese, but even if those benefits hold up, whether the same can be said of the Flat Belly Diet is unproven. Expand this section to see research on the Flat Belly Diet.

  • In a study commissioned by Prevention magazine, researchers tracked nine overweight women who were following the Flat Belly Diet. After 28 days, visceral belly fat mass had shrunk by an average of 33 percent. (Visceral belly fat, which lies deep inside the abdomen, surrounds the internal organs; having too much increases the risk of serious health problems, like heart disease and type 2 diabetes.) Participants also lost an average of 8.4 pounds and 2 inches off their waist during the study period, according to findings published in the February 2009 issue of Prevention.
  • A study published in Diabetes Care in July 2007 and conducted by scientists at Reina Sofía University Hospital in Córdoba, Spain, placed a group of overweight people on three 4-week diets with the same number of calories but one was high in carbs, one in monounsaturated fat, and one in saturated fat. Harmful belly fat built up in the participants on the high-carb plan but not in those on the two high-fat plans.
  • In another study, researchers tracked eight overweight or obese men who followed two diets for four weeks each. One diet was high in saturated fat, while the other was high in monounsaturated fat. Overall, the men gained fat mass while following the diet heavy on saturated fat and lost fat mass on the MUFA-rich diet. Men gained weight around the middle on the saturated-fat diet and lost it from the trunk and limbs on the MUFA diet, according to findings published in the British Journal of Nutrition in 2003. The researchers concluded that replacing saturated fat with monounsaturated fat can lead to a significant reduction in body weight and fat mass.

Does it have cardiovascular benefits?

Research is limited, but a MUFA-rich diet appears to have a positive effect. Healthy fats like MUFAs are good for the heart and most other parts of the body. And if the diet delivers on its promise to whittle down visceral belly fat—a risk factor for heart disease—your cardiovascular health will benefit. Plus, a Mediterranean-style approach has been associated with a decreased risk for heart disease, and it’s also been shown to reduce blood pressure and “bad” LDL cholesterol.

  • In the 2009 Prevention magazine study described above, women following the Flat Belly Diet for 28 days saw their total cholesterol drop 21 points, on average, and their “bad” LDL cholesterol drop 9 points. That’s on par with what most cholesterol-lowering drugs will deliver within a month.
  • A study published in 2010 in the Canadian Medical Association Journal  found that people with mild to moderately high cholesterol levels benefited by adding monounsaturated fat to their diet. Participants got 13 percent of their daily calories from MUFA-rich sunflower or avocado oil. After one month, their “good” HDL cholesterol increased by 12.5 percent, while their LDL dropped by 25 percent. (Boosting HDL is smart because HDL helps break down and flush out bad LDL cholesterol.)

Can it prevent or control diabetes?

Research suggests that MUFAs help stabilize blood sugar levels and control insulin, reducing the odds of diabetes. What’s more, being overweight and carrying torso fat are big risk factors for type 2 diabetes. If the Flat Belly Diet helps you lose weight—particularly from the abdominal area—and keep it off, you’re tilting the odds in your favor. Plus, research suggests following a Mediterranean-style diet may reverse or reduce the risk of developing metabolic syndrome, which can lead to type 2 diabetes and heart disease.

Flat Belly Diet! Diabetes begins with a 7-day startup plan, allows for slightly more calories than the standard diet, and outlines a walking routine to be followed six days a week. By eating certain foods in certain portions, the book authors say, you'll stave off two diabetes triggers: insulin resistanceand accumulation of visceral fat. This diet track is designed for people with type 2 diabetes.

Are there health risks?

No indications of serious risks or side effects have surfaced. However, if you have a health condition, talk with your doctor before making major dietary changes.

How well does it conform to accepted dietary guidelines?

Fat. You’ll have no problem staying within the government’s recommendation that between 20 to 35 percent of daily calories come from fat. A sample daily menu provided 26 percent.

Protein. It’s within the acceptable range for protein consumption—22 percent, compared with the 10 to 35 percent the government recommends.

Carbohydrates. The government advises that between 45 and 65 percent of daily calories come from carbs. Flat Belly should keep you at a middle-of-the-road 56 percent.

Salt. The majority of Americans eat too much salt. The recommended daily maximum is 2,300 milligrams, but if you’re 51 or older, African-American, or have hypertension, diabetes, or chronic kidney disease, the limit is 1,500 mg. A sample daily Flat Belly menu provided 1,453 mg.

Other key nutrients. The 2010 Dietary Guidelines call these “nutrients of concern” because many Americans get too little of one or more of them:

  • Fiber. Getting the recommended daily amount of 22 to 34 grams for adults helps you feel full and promotes good digestion. Veggies, fruits, beans, and whole grains—all major sources—are encouraged on this diet, so you should easily meet the recommendation. A sample daily menu provided 35 grams.
  • Potassium. A sufficient amount of this important nutrient, according to the 2010 Dietary Guidelines, counters salt’s ability to raise blood pressure, decreases bone loss, and reduces the risk of developing kidney stones. It’s not that easy to get the recommended daily 4,700 mg. from food. (Bananas are high in potassium, yet you’d have to eat 11 a day.) The majority of Americans take in far too little. A sample daily menu came up short at 2,479 mg.
  • Calcium. It’s essential not only to build and maintain bones but to make blood vessels and muscles function properly. Many Americans don’t get enough. Women and anyone older than 50 should try especially hard to meet the government’s recommendation of 1,000 to 1,300 mg. A sample daily menu provided 1,028 mg.
  • Vitamin B-12. Adults should shoot for 2.4 micrograms of this nutrient, which is critical for proper cell metabolism. Fish like salmon and trout, along with eggs and yogurt, are good sources.
  • Vitamin D. Adults who don’t get enough sunlight need to meet the government’s 15 microgram recommendation with food or a supplement to lower the risk of bone fractures. A sample daily menu skimped, providing 9.57 mcg. Just 3 ounces of sockeye salmon, which packs almost 20 micrograms of vitamin D, will satisfy the requirement.

Supplement recommended? No.

How easy is it to follow?

The Flat Belly Diet explains exactly what and when to eat. It even includes shopping lists. These resources take much of the hard work and planning out of dieting. However, sticking to a strict eating schedule—a meal or snack every four hours—can be daunting for busy dieters.


Recipes abound, though meal prep may be time-consuming. Eating out is doable, and alcohol is allowed. The company’s online and printed resources may be helpful.

Recipes. Flat Belly Diet! Family Cookbook and Flat Belly Diet! Cookbook are packed with breakfast, lunch, dinner, dessert, and snack recipes. Choices range from crab primavera with spaghetti to sweet-and-sour blueberry parfaits. All recipes include information on calories, protein, carbohydrates, fat, saturated fat, cholesterol, sodium, and fiber.

Eating out. Allowed. Check out restaurant menus beforehand to find meals that most closely resemble those in the book. Opt for safe bets like salad made of leafy greens, raw veggies, grilled chicken or salmon, and balsamic vinegar. Always bring two tablespoons of nuts to supplement meals at restaurants where MUFAs aren’t available. The Flat Belly Diet! Pocket Guide lists acceptable dishes at many popular restaurants.

Alcohol. Allowed. Moderation is key, i.e., one drink a day for women, and, two for men. If you do imbibe, you’ll have to compensate with exercise or by shaving 25 calories off your four meals (or 50 from two).

Timesavers. Detailed meal plans and grocery lists are provided.

Extras. Online membership at flatbellydiet.com includes tips from diet experts, message boards and a buddy network, a food journal, and success stories. You can also customize meal plans and store your shopping lists.


Nutrition experts emphasize the importance of satiety, the satisfied feeling that you’ve had enough. You shouldn’t feel hungry on the 1,600-calorie-a-day Flat Belly Diet. MUFAs help slow digestion, keeping you feeling fuller for longer. And you’ll be eating lots of fiber, which staves off hunger.


Recipes range from whole-wheat pizza to pork and pine nut meatballs; snacks include chocolate-drizzled popcorn and a peanut butter and yogurt smoothie. For dessert, try a lemon cupcake with citrus icing or pumpkin cream roll.

How much does it cost?

Online membership costs $19.95 per month, or $49.50 for three months. The Flat Belly Diet, an essential guidebook, is $15.99. Additional books range from $26.99 (Flat Belly Diet! Family Cookbook) to $7.99 (Flat Belly Diet! Pocket Guide). Following the meal plan is moderately pricey. Some ingredients, like olive oil, nuts, fish, and fresh produce, can be expensive.

Does the diet allow for restrictions and preferences?

Most people can customize the Flat Belly Diet to fit their needs—pick a preference for more information.

No problem. The Flat Belly books offer lists of vegetarian and vegan substitutions, as well as plenty of recipes. For example: stir-fried broccoli and mushrooms with tofu, spaghetti squash casserole, and chickpea salad.

People who can’t tolerate gluten, a protein found in wheat, barley, and rye, can easily follow the diet. The books include suggestions on gluten-free brands for a variety of food types.

Doable, but it’s up to you to check the nutrition information on recipes and keep track of your sodium intake. Most MUFAs are low in sodium, but olives are salty, so stick to one a day. When shopping for MUFA-rich foods like olive tapenade, pesto, and nut butters, reach for the low-salt varieties. Sodium-free seasonings like fresh or dried basil, rosemary, and thyme are also recommended.

Yes, you can make sure your diet is kosher.

Yes, but it’s up to you to ensure your food conforms.

What is the role of exercise?

Strongly encouraged, but not required. The Flat Belly Diet outlines an optional plan, including workout descriptions, intensity, and duration. It recommends cardio exercise to burn calories and shed fat; strength training to build muscle and boost metabolism; and core-focused exercises to tone and tighten the midsection.

Last updated by Angela Haupt | December 12, 2013

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