The 5 Bite Diet is a fad diet that promises impressive weight loss, all while allowing you to eat your favorite foods.

It’s marketed as an alternative to weight loss surgery, and its proponents rave about its easy-to-follow guidelines and quick results.

However, some find certain aspects of this diet worrisome, including the extremely low calorie content, potential lack of nutrients, and high risk of weight regain.

This article reviews the 5 Bite Diet and whether it works for weight loss.

  • Overall score: 0.79
  • Weight loss: 1
  • Healthy eating: 0.5
  • Sustainability: 1.5
  • Whole body health: 0
  • Nutrition quality: 1.25
  • Evidence based: 0.5

BOTTOM LINE: The 5 Bite Diet is a very-low-calorie diet that promises quick weight loss without counting calories, restricting food choices, or exercising. Though it may result in short-term weight loss, it has several downsides.

The 5 Bite Diet was created in 2007 by Dr. Alwin Lewis, as part of his book “Why Weight Around?”

This very-low-calorie diet promises quick weight loss without counting calories, giving up the foods you love, or following a regular exercise regimen.

It’s meant to provide you with the same weight loss results you would expect from a gastric bypass, which is a surgery that reduces the size of your stomach.

The diet suggests that followers can expect to lose as much as 15 pounds (6.8 kg) each week by limiting their food intake to just 5 bites per meal.

Over the years, several products have been derived from the original book, including one-on-one coaching packages and memberships to an online support forum geared toward helping readers maximize their weight loss success (1).


The 5 Bite Diet is a very-low-calorie diet promising to help you lose a lot of weight in a very short time, without surgery, special diet foods, counting calories, or exercising.

The 5 Bite Diet’s central premise is that by learning to eat like a person who has undergone gastric bypass surgery, you’ll shed the weight without needing the procedure.

Accordingly, the portion sizes are restricted to a maximum of 10–12 regular-sized bites of food per day. You may start on this plan immediately or gradually reduce your intake over a few days or weeks.

To achieve its guidelines, the 5 Bite Diet encourages you to skip breakfast, drinking only black coffee instead. You may then eat whatever you would like for lunch and dinner, as long as the total number of bites does not exceed five per meal.

Though no foods are off limits, at least one bite per meal — or a minimum of two per day — should come from a protein-rich source, such as meat, fish, eggs, dairy, tofu, or legumes.

You may also have a bite of food between meals for a maximum of two, one-bite snacks each day and drink unlimited amounts of calorie-free drinks.

Low-intensity exercise is allowed, but moderate- and high-intensity workouts should be avoided on this diet. To cover any potential nutrient deficiencies, it’s recommended to take a multivitamin and omega-3 supplement each day.

Once you reach your goal weight, you’re advised to switch to a more sustainable, nutrient-rich diet to maintain your weight loss.


On the 5 Bite Diet, no foods are off-limits, but you need to severely restrict the number of bites you take per meal or snack. Multivitamin and omega-3 supplements are encouraged to cover any nutritional gaps related to the diet.

As with all low-calorie diets, the 5 Bite Diet is likely to help you lose weight — at least initially.

Limiting the amount of food you eat to a maximum of 10–12 bites each day will naturally cause you to eat fewer calories than your body requires. Research consistently shows that such a calorie deficit will lead to weight loss, regardless of the foods you eat (2, 3, 4, 5).

Depending on your food choices, the 5 Bite Diet is very likely to provide you fewer than 800 calories per day, classifying it as a very-low-calorie diet (VLCD) (6).

According to experts, VLCDs come with their own set of health risks, including digestive issues, an increased risk of gallstones, and a higher likelihood of disordered eating (6).

In addition, evidence suggests that, despite helping people initially lose weight, this type of diet often leads to weight regain, which may increase your risk of depression and cause a sense of failure in people trying to manage their weight (6).

For these reasons, the 5 Bite Diet isn’t considered an appropriate way to lose weight for most people and should only be followed under medical supervision.


The 5 Bite Diet is likely to help you lose weight. However, this weight loss may be accompanied by several health risks. Plus, the risk of weight regain once you go off the diet is very high. This diet should only be followed under medical supervision.

The 5 Bite Diet may offer some benefits, most of which are linked to its ability to promote weight loss.

Proponents most frequently mention that the diet doesn’t place any restrictions on what you eat and only focuses on how much you eat. Therefore, dieters don’t have to give up their favorite foods to lose weight.

In addition, research shows that losing even as little as a 5–10% of your body weight can help reduce joint pain and your risk of type 2 diabetes (7, 8).

Studies further indicate that losing weight may lower risk factors for heart disease, such as triglyceride, LDL (bad) cholesterol, and blood pressure levels (8, 9).

The 5 Bite Diet emphasizes that the health risks of remaining overweight or having to undergo weight loss surgery far outweigh those caused by temporarily limiting the amount of food you eat.

Nevertheless, keep in mind that these benefits only truly occur if you’re able to sustain your weight loss. Research shows that this is rarely the case after following a VLCD like the 5 Bite Diet (6).


By helping you lose weight, the 5 Bite Diet may reduce joint pain and lower your risk of heart disease and type 2 diabetes. However, these benefits are likely negated by the high risk of weight regain.

As with all severely calorie-restricted diets, the 5 Bite Diet comes with several downsides.

May cause nutrient deficiencies

It’s nearly impossible to meet your nutrient needs by eating so few calories each day, even if your diet includes nutrient-rich foods. This can lead to side effects like fatigue, dizziness, constipation, and even loss of bone density (6).

The risk of nutrient deficiencies is especially high in those who need to lose considerable amounts of weight, as they follow this nutrient-restricted diet for longer.

The recommended daily multivitamin and omega-3 supplements can reduce the severity of some of these problems but don’t replace getting these nutrients directly from foods (10, 11).

Additionally, since dieters are allowed to choose whichever foods they like, highly-processed foods like fast food, candy, and chips may dominate calorie intake, which isn’t good for your overall health (12).

High risk of weight regain and disordered eating behaviors

Consistently eating fewer calories than your body needs may lead to muscle loss and slow your metabolism. In turn, a slower metabolism makes it more difficult to maintain your weight loss and increases your risk of weight regain over time (13, 14).

Evidence also suggests that severely restricting calories, as is encouraged with this diet, may increase your risk of binge eating behaviors. Therefore, this diet is especially unsuitable for people prone to or with a history of disordered eating behaviors (6).


The 5 Bite Diet makes it difficult to meet your nutrient needs. It may also increase your risk of disordered eating and cause your metabolism to slow, hampering your ability to maintain weight loss over the long term.

The 5 Bite Diet doesn’t place any restrictions on what you can eat.

You are allowed to eat everything you desire, as long as you limit your intake to 10–12 bites per day, which are ideally spread over 2 meals and 2 optional snacks each day.

However, the guidelines encourage you to include at least one bite of a protein-rich food at each meal, such as:

  • meat and chicken
  • fish and seafood
  • eggs
  • dairy
  • tofu, tempeh, and seitan
  • legumes like beans and peas

To help prevent nutrient deficiencies, the 5 Bite Diet also stresses the importance of taking a multivitamin and omega-3 supplement each day.


No foods are off-limits on the 5 Bite Diet. Still, protein-rich foods should be included at each meal. In addition, multivitamin and omega-3 supplements should be taken daily.

Here’s a three-day sample menu tailored to the 5 Bite Diet. Snacks are optional but included in this sample menu.

Day 1

  • Breakfast: coffee and a multivitamin
  • Snack: 1 bite of an apple
  • Lunch: 5 bites of an all-dressed hamburger or veggie burger and an omega-3 supplement
  • Snack: 1 bite of a snickers bar
  • Dinner: 3 bites of macaroni and cheese and 2 bites of a chocolate brownie

Day 2

  • Breakfast: coffee and a multivitamin
  • Snack: 1 bite of a mango
  • Lunch: 5 bites of taco stuffed with chicken, peppers, and avocados and an omega-3 supplement
  • Snack: 1 gulp of a fruit-and-yogurt smoothie
  • Dinner: 3 bites of cauliflower-crust pizza with your favorite toppings and 2 bites of a rhubarb pie

Day 3

  • Breakfast: coffee and a multivitamin
  • Snack: 1 bite of a banana
  • Lunch: 5 bites of spinach, cheese, and mushroom quiche and an omega-3 supplement
  • Snack: 1 bite of a granola bar
  • Dinner: 5 bites of spaghetti and meatballs

As you can see, people who follow the 5 Bite Diet can choose whichever foods they like, including high-calorie desserts, as long as the 10–12 bite per day rule is followed.


The 5 Bite Diet affords you the option to enjoy your favorite meals and leaves it up to you to decide how many nutrient-rich foods to include in your daily menu.

The 5 Bite Diet is a fad diet that promotes severe calorie restriction in an attempt to promote quick weight loss.

It may slow your metabolism and increase your risk of weight regain.

In addition, this diet is not nutritionally adequate and may lead to nutrient deficiencies and long-term health consequences.

It’s unsuitable for most people, and those curious to try it should only do so under medical supervision.