17 Day Diet Overview

Pros & Cons

  • Flexible
  • Nutritionally sound
  • Somewhat expensive
  • Meal prep required

Do's & Don'ts

Do: Enjoy your favorite foods, be it pizza or French fries, but only on the weekends See more Do's & Don'ts

Overview

Type:

Balanced.

Resembles these U.S. News-rated diets:

Biggest Loser Diet, Mayo Clinic Diet

The aim:

Quick, but healthy weight loss without hunger.

The claim:

Lose 10 to 15 pounds in just 17 days.

The theory:

The diet prescribes a slightly different eating and exercise regimen in each of its four cycles to promote “body confusion”—a way to prevent your body from adapting so your metabolism stays in high gear and you burn lots of fat. While this theory may not be scientifically proven, the balanced meals and exercise you’ll get should help you shed pounds.

Note:

This diet has not been ranked by U.S. News.

How does the 17 Day Diet work?

Based on Michael Rafael Moreno’s 2011 book, The 17 Day Diet: A Doctor’s Plan Designed for Rapid Results, the regimen is purportedly built to help you shed pounds quickly and permanently. The diet is divided into three 17-day cycles to prevent boredom and your body from plateauing, says Moreno, a California-based family medicine physician. In the first cycle, “Accelerate,” you’ll cut back to about 1,200 calories per day, reduce your sugar intake, and focus on improving your digestion. This is when you’ll lose the most—10 to 15 pounds—though most of it will be water weight, he says. After 17 days you’ll reach the second cycle, “Activate.” During this period you’ll alternate between Accelerate’s limited-calorie diet and Activate’s slightly higher-calorie meal plan. This back-and-forth supposedly resets your metabolism and stimulates fat burning to yield an additional loss of 5 to 6 pounds. In the third cycle, “Achieve,” you’ll focus on developing good eating habits to drop another 2 to 3 pounds. The final cycle, “Arrive,” is ongoing. You’ll maintain your goal weight by eating healthfully on weekdays and enjoying your favorite foods (in moderation) on the weekends.

You can build your own meal plans using Moreno’s lists of acceptable lean proteins, non-starchy vegetables, low-sugar fruits, and natural carbohydrates, including some general portion guidelines. Need more structure? Moreno offers 17 sample menus for each cycle. Green tea pops up in every meal because Moreno is a big believer in its fat-fighting properties, claiming that it blocks the growth of blood vessels in fatty tissue.

Moreno also offers tips for dieting on the road, at restaurants, during the holidays, for different cultural cuisines—and even if you’re PMS-ing.

Will you lose weight?

Likely. It’ll be hard not to lose weight with the balanced diet and regular exercise this diet prescribes, as long as you don’t gorge on the weekends. It’s unclear whether the cycles themselves promote weight loss—no studies have specifically evaluated the 17-day-diet—and “body confusion” has not been scientifically proven.

Does it have cardiovascular benefits?

Unclear, but its meals are low in fat, cholesterol, and sugar, which should decrease your risk of heart disease and high blood pressure. Regular exercise will also strengthen your heart and lower your chances of high cholesterol, high blood pressure, and clogged arteries (atherosclerosis).

Can it prevent or control diabetes?

No studies have looked at the 17-day diet for diabetes, but balanced eating and regular exercise can help prevent and control the condition.

Prevention: Being overweight is one of the biggest risk factors for type 2 diabetes. If this diet helps you lose weight and keep it off, you might tilt the diabetes odds in your favor.

Control: A diabetes diet should be low in sugar and refined carbohydrates to keep blood sugar levels in check—this regimen limits both. And because there are no rigid meal plans or prepackaged foods, you can ensure that what you’re eating doesn’t go against your doctor’s advice.

Are there health risks?

Not likely, but if you have any health conditions, consult your doctor before trying the 17-day diet.

How well does it conform to accepted dietary guidelines?

Fat. During cycle 1, you’ll get slightly less than the government’s recommended 20 to 35 percent daily calories from fat. During cycle 4, you’ll be squarely within that range, at 24 percent.

Protein. You’ll definitely get enough. During the first cycle, 39 percent of daily calories will come from protein, above the recommended range of 10 to 35 percent. And during cycle 4, you’ll get 33 percent.

Carbohydrates. At 46 and 32 percent for cycles 1 and 4, this diet is on the lower end of the acceptable range of 45 to 65 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, that limit is 1,500 mg. This diet provides 1,875 and 1,961 mg. during cycles 1 and 4.

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. During cycle 1, the 17-day diet goes slightly over the mark with 35 g., but during cycle 4, it falls below, with just 15 g.
  • 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 to get enough.) The majority of Americans take in far too little. This diet offers just 1,852 mg. and 1,290 mg. during cycles 1 and 4.
  • 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 day. This diet falls far short at 420 mg. and 443 mg. during cycles 1 and 4.
  • Vitamin B-12. Adults should shoot for a daily 2.4 micrograms of this nutrient, which is critical for proper cell metabolism. The sample menus provide more than enough.
  • Vitamin D. Adults who don’t get enough sunlight need to meet the government’s recommended 15 micrograms a day with food or a supplement to lower the risk of bone fractures. With this diet, you’ll get less.

Supplement recommended? N/A

How easy is it to follow?

Sticking to the 17-day diet is doable.

Convenience:

It’s relatively convenient—Moreno provides tailored meal plans for the holidays and busy work schedules, for example. But the diet entails significant food prep and shopping, which are time-consuming.

Recipes. Moreno offers recipes at the back of his book and on his website, but you can use your own, too, as long as they conform to his guidelines.

Eating out. Moreno devotes an entire section of his book to eating out and lists the most fattening restaurant items to be aware of. If you know what’s in your food and order accordingly, you should be fine.

Alcohol. You’re allowed one drink per day during the last two cycles, but you’re strongly advised to pass when you can.

Time-savers. None.

Extras. None.

Fullness:

Moreno says your meals should dispel hunger, but not make you feel full or stuffed. Many items don't come with strict portion sizes, so you can eat until you feel satisfied.

Taste:

You’re on the hook for meal prep and food selection: Dishes will be as good as you make them. If you don’t like vegetables, prepare to expand your horizons.

How much does it cost?

You’ll be buying lots of fresh produce, fish, and meat, so this diet could get pricey. But you can shop where you want and “organic” foods aren’t required.

Does the diet allow for restrictions and preferences?

Most people can customize the 17-day diet to fit their needs—pick a preference for more information.

Yes. Moreno says you can swap out animal proteins for vegetarian or vegan substitutes, and have a probiotic supplement in lieu of yogurt.

Yes, but it’s up to you to make sure your menu conforms.

Yes. Moreno’s recipes call for very little salt, just make sure you ignore the salt shaker when you eat.

Yes, but it’s up to you to make sure your meals conform.

Yes, just choose items that fit your needs.

What is the role of exercise?

Exercise is a key component of the 17-day diet. During the first and second cycles, you’ll spend 17 minutes each day doing light exercise, like walking. During the third cycle, you’ll do 40 to 60 minutes of aerobic exercise “most” days of the week. In the final cycle, you’ll exercise for an hour on weekends and keep up your regular regimen on weekdays.


See more Eat + Run posts »

Best Diets Rankings

Best Diets Overall
Diets ranked by across-the-board effectiveness.

Best Weight-Loss Diets
Diets ranked by effectiveness for both quick and lasting weight loss.

Best Diabetes Diets
Diets that can prevent diabetes or help diabetics.

Best Heart-Healthy Diets
Diets that lower cholesterol, blood pressure or triglycerides.

Best Diets for Healthy Eating
Diets ranked by how safe and nutritionally complete they are.

Best Commercial Diet Plans
Brand-name diets ranked by overall effectiveness.

Easiest Diets to Follow
Diets ranked on whether they're a snap to stick to.

Best Plant-Based Diets
Plant-based diets ranked by overall effectiveness.

Connect with U.S. News Health