The 17-Day Diet promises quick weight loss of 10 to 15 pounds through a restrictive first phase that eliminates sugar, grains, fruit, and most dairy foods. The plan claims to rev up your metabolism and burn body fat.

The program is the brainchild of Michael Moreno, MD whose book, "The 17-Day Diet," was published in 2010 and has helped millions lose weight, according to Moreno. His weight-loss blueprint was updated in 2014 with "The 17-Day Diet: Breakthrough Edition," which includes recipes.

The 17-Day Diet peaked in popularity in the early 2010s and still circulates in diet culture. Proponents tout its fast results (especially during the first 17 days). However, as with many diets, it's tricky to get sustained results, and people who have followed the 17-Day Diet say it's difficult to follow long-term.

Realistically, you are likely to lose weight on the 17-Day Diet, particularly in the first phase. The diet gets slightly less restrictive in the subsequent phases and ultimately adds back many of the foods it eliminates by the final cycle, which is ideally meant to be followed for life. Reintroducing foods previously eliminated can cause you to regain some or all initial weight lost.

What Can You Eat on the 17-Day Diet?

The eating plan on the 17-Day Diet reduces your carbohydrate intake by eliminating all refined carbohydrates and sugars. The diet does allow for whole grains and prioritizes low-carb vegetables, lean protein, and healthy fats. The 17-Day Diet works in cycles, with different foods allowed during the cycles.

The diet includes three meals per day plus snacks to keep people satiated. From the first 17 days, you can eat as much as you want of specific proteins and the so-called "cleansing" (e.g., non-starchy) vegetables.

The diet blueprint includes suggested meal plans for all days, although you can mix and match those plans to suit your tastes. In addition, you can elect to fast in between cycles (drinking smoothies) to jumpstart your weight loss.

To participate in the 17-Day Diet, you can buy Moreno's book (although not required) with meal plans, recipes, and the diet blueprint. Most meal templates are simple. For example, a typical breakfast in Cycle 2 includes 1 cup of granola with 6 ounces of no-sugar-added fruit-flavored yogurt, and a typical dinner would feature garlic shrimp, steamed green beans, and a large tossed salad dressed with 1 tablespoon olive oil.

What You Need to Know About the 17-Day Diet

If you have food allergies or intolerances, following the 17-Day Diet should be relatively simple—eliminate foods you can't have. For those with nut or dairy allergies, it's easy since those foods are mostly not included in the diet blueprint. You'll find the 17-Day Diet easy to follow if you're gluten-free since it mentions when you can have food like gluten-free bread and pasta.

The program also includes "transitional day fasts," which are supposed to "coax your body into additional fat-burning between cycles." These fasts are optional, according to Moreno. If you do the transitional fasts, you'll consume smoothies in three liquid meals those days. Smoothies contain almond milk, yogurt, whey powder, powdered fiber, and fruit.

There are four phases, or "cycles," on the 17-Day Diet, the first three of which are 17 days long. Here's a breakdown of each cycle:

• Cycle 1 ("Accelerate") is designed to "promote rapid weight loss by improving digestive health. It helps clear sugar from the blood to boost fat-burning and discourage fat storage," according to Moreno. This cycle reduces carbohydrate intake slightly but eliminates all sugar, sweets, and refined carbohydrates such as bread and pasta, replacing them mainly with low-carb vegetables. You're allowed fat like olive oil or flaxseed oil, plus "liberal amounts" of lean protein. Probiotic foods such as yogurt, kefir, and tempeh also are encouraged.
• Cycle 2 ("Activate") is designed to "reset your metabolism through a strategy that involves increasing and decreasing your caloric consumption to stimulate fat burning and to help prevent plateaus." During this cycle of the 17-Day Diet, you'll alternate days between the more restrictive Cycle 1 foods and less restrictive Cycle 2 foods. On "Cycle 2" days, you can have everything allowed in Cycle 1, plus some higher-fat meats and fish, whole grains, starchy vegetables, and legumes.
• Cycle 3 ("Achieve") is designed to help you "develop good eating habits through the reintroduction of additional foods and move you closer to your goal weight." Cycle 3 foods include all foods from the first two cycles, plus some additional fattier types of meat (quail and turkey bacon, for example). You also can have some forms of whole-grain bread, high-fiber cereals, and whole-grain pasta. Vegetables are unlimited, and you can have two servings of fruit daily. Alcoholic beverages are allowed in moderation.
• Cycle 4 ("Arrive") is designed for the long term to "keep you at your goal weight through a program of eating less that lets you enjoy your favorite foods on weekends while eating healthfully during the week." This open-ended cycle calls for eating 0only foods allowed in the first three cycles during the week and then giving yourself leeway to "splurge" on one to three meals with alcohol between Friday dinner and Sunday dinner.

The 17-Day Diet focuses on eliminating certain carbohydrates from your meals. As a result, you'll tend to eat more protein than you might normally while eliminating entire groups of carb-based foods.

Protein

There are plenty of protein options on the 17-Day Diet, even starting in the diet's more restrictive first cycle. From day one, you can enjoy fish (salmon, sole, flounder, catfish, tilapia, and canned light tuna in water). You also can have chicken and turkey breast, lean ground turkey, and eggs in limited quantities. In the second cycle, you can add shellfish, pork, lean red meat, lamb, and veal. In the third cycle, you can have fatty types of poultry plus turkey bacon, turkey sausage, and Canadian bacon.

Vegetables

When it comes to vegetables, the 17-Day Diet breaks them down into two categories: starchy and non-starchy. Non-starchy vegetables or "cleansing vegetables" are allowed in unlimited quantities. They include cauliflower, cabbage, broccoli, Brussels sprouts, asparagus, celery, green beans, greens, mushrooms, onions, and tomatoes. Starchy vegetables are allowed beginning in Cycle 2. They include corn, potatoes, pumpkin, sweet potato, and winter squash.

Fruit

Fruits are also divided into two categories: low-sugar fruit and high-sugar fruit. Two servings per day of low-sugar fruit are allowed from the first cycle, while high-sugar fruit isn't allowed until the third cycle. This diet categorizes low-sugar fruits as apples, berries, grapefruit, oranges, peaches, pears, plums, prunes, and red grapes. High-sugar fruits include apricots, bananas, cherries, figs, kiwi, mango, papaya, pineapple, tangelo, and tangerines.

Grains

The diet bans grains and other "natural starches" in Cycle 1, but then allows them (limited in types and quantities) in Cycles 2 and 3. In Cycle 2, you can add amaranth, barley, brown rice, couscous, cream of wheat, grits, long-grain rice, millet, oat bran, old-fashioned oatmeal, and quinoa. In Cycle 3, your grain-based options expand dramatically, with whole-grain and gluten-free bread, high-fiber cereals, plus various kinds of pasta (whole wheat, gluten-free, vegetable-based, and high-fiber).

Dairy

Dairy products are allowed in moderation on the 17-Day Diet. In Cycles 1 and 2, followers are encouraged to have two servings per day of probiotic foods, which include yogurt, kefir, and acidophilus milk, along with Breakstone Live-Active cottage cheese (with active cultures).

In Phase 3, followers can add certain cheeses (Brie, camembert, fontina, low-fat cheddar, Edam, feta, goat, Limburger, and part-skim mozzarella). They also can enjoy low-fat cottage cheese, low-fat milk, and low-fat ricotta cheese.

Fats

When it comes to fats, Dr. Moreno encourages people following his program to consume 1 to 2 tablespoons of "friendly fats" (olive oil and flaxseed oil) from the first day. Once they get to Cycle 3, they also can have a small amount of avocado, canola oil, walnut oil, mayonnaise, nuts or seeds, reduced-calorie margarine, and salad dressing per day.

Sample 17-Day Diet Shopping List

The 17-Day Diet is divided into four cycles, and what you eat will vary depending on the cycle. The most restrictive phase of the diet is Cycle 1, but the eating plan starts to ease up during Cycle 2. On "Cycle 2" days, you can eat everything allowed during Cycle 1 plus higher-fat protein, whole grains, starchy vegetables, and legumes.

The following shopping list includes the basics for Cycle 2 and includes foods from Cycle 1. This is not a definitive shopping list and you may find other foods work better for you.

Cycle 1: Accelerate

• Low-carb vegetables (asparagus, zucchini, broccoli)
• Olive oil and flaxseed oil
• Lean protein (tofu, white-fleshed fish, low-fat cottage cheese)
• Low-sugar fruit (mixed berries, grapefruit, avocado)
• Probiotic foods (kefir and tempeh)

Cycle 2: Activate

• Higher-fat meats and fish (chicken, beef, pork, salmon, shrimp)
• Whole grains (quinoa, brown rice, barley, low-fat granola, rolled oats)
• Starchy vegetables (potatoes, sweet potatoes, butternut squash)
• Legumes (chickpeas, beans, lentils)
• Fruits (apples, nectarines, pears, grapes)
• No-sugar-added yogurt (plain or with fruit added)

Sample 17-Day Diet Meal Plan

Once you get to Cycle 2, you will alternate between low-calorie foods from Cycle 1 and higher-calorie foods from Cycle 2 every other day for 17 days. From there, you'll move on to Cycle 3. The following three-day meal plan is an example of what you could eat during the first three days in Cycle 2. Note that on the 17-Day Diet, there may be other meals more appropriate for your tastes and preferences.

Day 1: Cycle 2

• Breakfast: 1 cup no-sugar-added fruit-flavored yogurt, 6 ounces low-carb, low-sugar granola
• Lunch: 1 cup Asian shrimp salad (omit sugar from the dressing)
• Dinner: 1 serving chicken marsala; 1 cup brown rice; 1 cup steamed broccoli

Day 2: Cycle 1

• Breakfast: 2 poached eggs; 1 cup plain kefir; 1/2 a grapefruit
• Lunch: 2 black sesame tofu summer rolls with peanut dipping sauce (omit brown sugar)
• Dinner: 3 ounces pan-seared halibut; 1 serving oven roasted asparagus

Day 3: Cycle 2

• Breakfast: 1 cup cooked oatmeal topped with sliced nectarines or peaches
• Lunch: 1 cup Greek yogurt almond chicken salad; a handful of whole-wheat rosemary crackers
• Dinner: 5-ounce serving honey mustard herbed salmon; 1 1/4 cup oven roasted potatoes; 3-ounce side spring mix greens

Pros and Cons of the 17-Day Diet

Though some health experts say the evidence for the 17-Day Diet is lacking, according to Moreno's website there is science behind it. Review the pros and cons to inform your decision about trying this diet.

Pros

• Lots of veggies and lean protein. The 17-Day Diet's cycles include loads of healthy non-starchy vegetables and lean protein. In fact, you're allowed unlimited amounts of both in all phases of the diet. These should help prevent hunger in the diet's early days.
• Adaptable to dietary restrictions. If you have celiac disease, a dairy intolerance, or a nut allergy, you can easily tailor the program to meet your needs. Choices are expansive enough to avoid allergenic foods and still follow the diet.
• Weight loss is likely. You're almost certain to lose weight, especially in the diet's early days, because your calories will be pretty limited, even though you can have unlimited lean protein and non-starchy vegetables. Initial weight loss can boost motivation and may also improve energy and sleep, which can help you stay on track with your new healthy eating plan.

Cons

• Not enough fiber. Everyone needs fiber—in fact, the U.S. Department of Agriculture's 2020–2025 Dietary Guidelines for Americans recommend anywhere from 22–28 grams of fiber per day for adult women and 28–34 grams for adult men. If you are not careful with planning out your meals in the first cycle, you could fall shy of your fiber needs. Be sure to incorporate lots of non-starchy vegetables and two servings of high-fiber fruits daily to meet your needs.
• Confusing to follow. The initial phase of the 17-Day Diet can be difficult to follow as it has specific rules and food restrictions. However, later stages appear to be more balanced. Some may find it time-consuming to prep and cook compliant meals, however, the recipes are fairly simple.

Is the 17-Day Diet a Healthy Choice?

The first cycle of the plan eliminates certain food groups such as whole grains and fruits, but these foods are added back over time. Therefore, the first cycle of the diet doesn't follow the USDA's dietary guidelines, but as you continue to follow the plan the diet becomes more balanced.

The USDA's MyPlate nutritional guidelines tool recommends you fill more than one-quarter of your "plate" (as in your daily diet) with grains—ideally with whole grains. The 17-Day Diet, of course, doesn't allow any grains in its first cycle, and after that allows a limited amount of grain-based products.

The USDA also advises a reduction of 500 calories a day for a steady rate of weight loss. On a 2,000-calorie diet that would mean taking in about 1,500 calories per day, but this can vary based on factors like age, gender, weight, and level of physical activity. Use this calculator to help determine your calorie guidelines.

Health Benefits

While proponents of the 17-Day Diet claim that it will speed up the body's metabolism and lead to increased weight loss, research suggests that any weight loss resulting from temporary diets is often not sustained. Even though the fourth phase of the diet is meant to be lifelong, many people may have a hard time sticking with it.

However, the eating plan does tout the benefits of cutting back on refined carbohydrates and added sugars and emphasizes lean protein and fresh vegetables, which could help people develop healthy eating habits.

Health Risks

While there are no common health risks associated with the 17-Day Diet, it does lack dietary fiber during the first cycle. Research shows that getting enough fiber is necessary for maintaining digestive health, reducing inflammation, and preventing colon cancer.

A Word From Verywell

Choosing a diet program is an individual decision, and what's right for you may not be right for someone else. If you're looking for a program that will lead to results, the 17-Day Diet could work for you—especially in the short term. Talk to your doctor before starting any diet to ensure it aligns with any health concerns.

Restricting your diet isn’t the only factor influencing weight loss. You can cultivate other healthy habits such as regular exercise, sleep, and other factors. If the 17-Day Diet gives you a jumpstart to make healthier choices, that's great—just be sure those choices are sustainable.

Remember, following a long- or short-term diet may not be necessary for you, and many diets out there don’t work, especially long-term. While we do not endorse fad diet trends or unsustainable weight-loss methods, we present the facts so you can make an informed decision that works best for your nutritional needs, genetic blueprint, budget, and goals.

If your goal is weight loss, remember that losing weight isn’t necessarily the same as being your healthiest self, and there are many other ways to pursue health. Exercise, sleep, and other lifestyle factors play a role in your overall health. The best diet is always the one that is balanced and fits your lifestyle.