What Is the GM Diet?

Six bananas, one peeled, on a bright blue background
Getty Images / Anjelika Gretskaia.
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The GM Diet, formally the General Motors Diet, is a seven-day diet plan that promises to help you lose an eyebrow-raising number of pounds—up to 17—in just one week. One GM Diet website even purports that you can lose 10 to 17 pounds in one week without exercising at all. If that’s not enough of a red flag to keep you away from the GM Diet, perhaps the rest of this guide will clarify just how strange and unnecessary the GM Diet is.

What Experts Say

“The GM diet includes healthy foods but is very regimented in how and when to eat them. For example, you can only eat fruit on the first day. The diet is unrealistic and not backed by science. Creating strict rules around food is not the healthiest psychologically.”

Kelly Plowe, MS, RD

Background

Supposedly, the GM Diet was developed for employees of General Motors, Inc in the 1980s. All across the Internet, you’ll find websites that claim the GM diet was formulated in conjunction with the United States Department of Agriculture (USDA) and Food and Drug Administration (FDA) and was “field-tested” at John Hopkins University.

However, no reputable websites purport any of those claims—only sites that do not include peer-reviewed scientific studies or input from dietary experts do say those things—and in 2009, a General Motors spokesperson “concluded it’s an urban myth” in an opinion article penned by Robert Cohen in the New York Times. 

If you peruse the FDA, USDA, and John Hopkins websites, you’ll find no mention of the GM diet, which is a good thing, because this so-called miracle diet isn’t backed by any science whatsoever (to see for yourself, search the PubMed database of research studies for the GM Diet). It’s also been referred to as the GM Detox Diet, which is yet another red flag, because self-imposed detoxes of any type may not be a good idea. 

If you were to give any credit to the original creators of the GM Diet (whoever they may be, as the origins of the diet remain unknown), you could at least say that back in the 1980s, not many people knew that fad diets were useless. 

Anyhow, the GM Diet seems to have persisted for quite some time, as people are still posting about it on various Internet channels, including social media, blogs, and forums. Though Verywell Fit doesn’t recommend the GM Diet as a bonafide weight-loss diet or as a sustainable healthy diet, it is worth discussing, if only to debunk its falsities.  

How It Works

The GM Diet is a seven-day weight loss diet plan. It involves eating specific foods on specific days, cutting out many food groups and beverages, and drinking something called “GM Wonder Soup” when you get hungry. If that sounds odd to you, it’s only going to get weirder—this section explains in full detail the oddities of this origins-unknown diet. 

What to Eat

The selection of foods you get to eat on the GM Diet isn’t necessarily bad (they’re all healthful foods in their own right), but the combinations in which you’re allowed to eat them does seem strange, and can even contribute to troubling mindsets about food combining, which may lead to disordered eating habits if you follow the diet for longer than its intended seven days.

Compliant Foods
  • Fruit

  • Vegetables

  • Potatoes

  • "GM Wonder Soup"

  • Milk

  • Beef, chicken, fish

  • Tomatoes

  • Brown rice (vegetarians only)

  • Cottage cheese (vegetarians only)

Non-Compliant Foods
  • Processed packaged foods of any sort, including chips, crackers, pretzels, cakes, cookies, ice creams, other desserts, granola bars, frozen meals, etc.

  • Grains, such as bread and oats (except for vegetarians, who may eat brown rice in place of protein sources)

Recommended Timing

On the GM Diet, there’s no such thing as “recommended timing"—it’s mandatory. You can actually eat at whatever time of day suits you, but throughout the week, you’re only allowed to combine certain foods with each other on particular days. 

Here’s an outline of the diet structure: 

  • Day 1: Fruit only. Eat any kind of fruit except bananas. The diet encourages you to eat melons for extra weight loss, although there are no studies that say melons specifically induce weight loss. 
  • Day 2: Vegetables only, raw or cooked. Limit potatoes to your morning meal.
  • Day 3: Eat fruit and vegetables of any kind, except bananas. 
  • Day 4: Only bananas and milk allowed. Eat up to 6 large or up to 8 small bananas, and drink three glasses of milk. The diet encourages you to drink skim milk, but doesn’t ban whole or 2% milk. 
  • Day 5: Two 10-ounce portions of beef, chicken, or fish. Other than the meat, you’re only allowed up to six tomatoes (yes, six whole tomatoes) on this day.
  • Day 6: Two 10-ounce portions of beef, chicken, or fish, plus unlimited vegetables, but no potatoes. 
  • Day 7: Only brown rice, fruit, fruit juice, and vegetables.

Interestingly enough, the GM Diet doesn’t specify any calorie limits or food quantity limits. You’re free to eat as much as you want, although eating too much of any type of food can be a detriment to your weight loss progress. You may not have an issue with that on the GM Diet, though, because all of the allowed foods are relatively low-calorie. This means you can eat a higher volume of food but take in fewer calories. 

When you get hungry in between meals, the GM Diet encourages you to eat “GM Wonder Soup,” a supposed weight-loss concoction made of celery, tomatoes, onions, bell peppers, and cabbage. While those ingredients aren’t at all bad for you, it’s improbable that this so-called Wonder Soup will help spur weight loss. 

Note: On each day where protein intake is required, vegetarians can substitute in brown rice or cottage cheese in place of chicken, beef, or fish. Keep in mind that while the protein content of cottage cheese might be somewhat comparable to animal sources of protein, the protein content of brown rice is not. 

Modifications

If you modify the GM Diet, you technically wouldn’t be doing the GM Diet anymore. I suppose you could modify the diet to match your dietary preferences, such as if you’re on a vegan or vegetarian diet. But to be truthful, in terms of food selection, the GM Diet is rather inclusive—you can eat any kind of fruit and vegetables, potatoes, dairy products, and several protein sources—and you can choose based on your preferences. 

The diet does leave out grains and healthy fats, but to add those back in would be to ignore the structure of the GM Diet. That’s not necessarily a bad thing, though: You do need nutrients from those food groups for optimal health. 

Pros
  • Includes healthy foods

  • Doesn’t restrict calories

  • Emphasizes hydration

Cons
  • Strange, unsustainable setup

  • May lead to a strained relationship with food

  • Claims not backed by science

  • Lacks important nutrients

Pros

Despite its peculiarity and unsustainable structure, the GM Diet does hold onto—if only by a thread—some notable health attributes. Here are the few:

Includes Healthy Foods

If the (unknown) creators of the GM Diet did anything right, it was that they chose a healthy group of foods. The health benefits may be near null because of the diet structure, but nonetheless, the food choices—fruit, vegetables, animal protein, milk, and vegetable-based soup—do offer health benefits in their own right. 

There is limited evidence that eating fruit as snacks can aid in weight loss (as opposed to eating processed snacks), but eating only fruit in a day can cause blood sugar spikes and crashes without protein and fat to help slow digestion. 

Doesn’t Restrict Calories

One of the very notable things about the GM Diet compared to its other fad diet counterparts is that it doesn’t emphasize calorie restriction. Perhaps the creators of the diet were smart enough to know that eating mostly fruit and vegetables does indeed lend itself to weight loss because produce has a low calorie density

Of course, on the days you eat animal protein foods and drink milk, your calorie intake will be higher than on the fruit- or vegetable-only days. Still, there’s no emphasis on calorie counting on any of the days, which is an upside for people who struggle with keeping track of calories. It is also one less thing to worry about when the rest of the diet requires so much pondering and planning.

Emphasizes Hydration

One other great thing about the GM Diet is its focus on fluids. For one, the diet encourages you to drink a vegetable, broth-based soup, which is a great way to consume fluids and nutrients at the same time (just watch your sodium intake). But besides the soup, the GM Diet emphasizes hydration and encourages you to consume plenty of water with and in between all of your meals. 

Cons

Don’t let the above benefits fool you into thinking the GM Diet is a sustainable, healthy eating pattern—it’s our duty to inform you of both the benefits and the drawbacks of every diet, but it does seem that the cons of the GM Diet heavily outweigh the pros. 

Strange, Unsustainable Setup

It goes without saying that the GM Diet is downright peculiar. The seven-day plan with seemingly arbitrary food combinations doesn’t lend itself to sustainability even for one week. Most people might start the diet, make it a day or two or even three in, and realize how silly or strained it feels. Plus, when hunger really strikes, who wants to drink vegetable soup instead of reaching for a hearty meal or snack?

Even if the bold claim of “up to 17 pounds lost in one week” is true (which it is very likely not), that’s not a manageable way to lose weight. Think about it with a long-term mindset: If you did lose 17 pounds in one week, what would you do next? How would you maintain your new weight?

Those are questions you must ask yourself when considering a diet like the GM Diet. Because if you gain those 17 pounds right back, those 8 bananas you ate on day four were all for naught. Instead of trying to lose weight rapidly, consider the generally accepted guidelines of losing one to two pounds per week, which you can accomplish through a daily calorie deficit.

May Lead to a Strained Relationship with Food

Any diet that restricts food groups can lead to disordered eating habits. This is something you should consider when weighing your diet options, especially if you have struggled with disordered eating or a full-fledged eating disorder in the past. If you tend to moralize foods—that is, give foods “good” and “bad” labels—the GM Diet may not be right for you. You may fare better with a diet that doesn’t impose such restrictive rules and allows you to eat a wide variety of nutritious foods and treats. 

Claims not backed by science

Evidence-based diets (a handful of which we provide at the end of this article) are the best diets to follow. When a diet has the endorsement of scientific organizations, the dietary branches of the government, and researchers in several disciplines, you know it’s a nutritious, manageable choice. 

But when a diet makes very bold claims that aren’t backed by any peer-reviewed scientific studies or prominent, trustworthy organizations— not to mention unlawfully assigns itself to the name of a well-known brand that has nothing to do with nutrition or healthy living—it doesn’t seem so worthy of trust. 

Lacks Important Nutrients

Of all the disadvantages to the GM Diet, this may be the most significant. While the GM Diet does include some nutritious foods, it leaves a glaringly wide gap in your nutrient intake because it completely cuts out two major food groups: grains (unless you’re vegetarian and choose to eat brown rice) and healthy fats. 

Without whole grains, you may find yourself struggling with a severe lack of energy (carbs are your body’s preferred source of energy ), and without healthy fats, well, a whole host of unfavorable outcomes can occur.

How It Compares

The GM Diet is somewhat one-of-a-kind. It’s tough to compare it to conventional diets because there are really no similarities between the GM Diet and a lifelong healthy eating pattern. 

Even U.S. News and World Report’s Best Diets rankings don’t include the GM diet, which should give you an even better idea of how untrustworthy its origins are—U.S. News and World Report covers the most prominent diets every year and ranks them according to their health benefits.

There are, however, some fad diets we can compare it to (see under Similar Diets below), and we can see how the GM Diet stacks up against the USDA healthy eating recommendations for Americans. 

USDA Recommendations

The federal dietary recommendations include five food groups: fruits, vegetables, grains, dairy, and protein. The key recommendations in the federal guidelines include:

  • “A variety of vegetables from all of the subgroups—dark green, red and orange, legumes (beans and peas), starchy, and other
  • Fruits, especially whole fruits
  • Grains, at least half of which are whole grains
  • Fat-free or low-fat dairy, including milk, yogurt, cheese, and/or fortified soy beverages
  • A variety of protein foods, including seafood, lean meats and poultry, eggs, legumes (beans and peas), and nuts, seeds, and soy products
  • Oils
  • Limited saturated fats, trans fats, added sugars and sodium”

In terms of food options, the GM Diet does surprisingly fall in line with many of the USDA recommendations. However, you should note a few key things: 

  • The GM Diet leaves out healthy sources of whole grains, such as whole-wheat bread, oats, quinoa, and barley, all of which are great sources of important vitamins and minerals. 
  • The GM Diet also leaves out healthy fats, such as nuts, seeds, olive oil, and avocados, which contain nutrients essential to your overall health. 
  • There is no calorie limit on the GM Diet, so you might inadvertently surpass your daily calorie needs. On the flip side, you might not meet your calorie needs because most of the foods on the GM Diet are low-calorie. 

Calorie Information

In order to reach your weight loss and health goals, it’s important to know how many calories you should be consuming each day, no matter if your goal is to lose weight, gain weight. or maintain your current weight. 

While most people need around 2,000 calories per day, some people may need less or more. For example, petite women and children may need fewer than 2,000 calories each day, while very active people (male and female) and men may need more than 2,000 calories each day. 

Your calorie needs differ from everyone else’s, with your age, height, weight, body composition, and activity level all playing a role., so don’t base your calorie intake on a friend, family member, colleague, partner, trainer, or anyone else. 

Similar Diets

As mentioned above, the GM Diet isn’t really comparable to a sustainable healthy eating pattern. It is, however, comparable to a handful of other fad diets that are just as curious and potentially dangerous. 

The Cabbage Soup Diet: This diet, as you might’ve inferred from its name, involves eating a lot of cabbage soup. Actually, the Cabbage Soup Diet is eerily similar to the GM Diet: It’s a seven-day quick weight loss plan that restricts foods to certain days. You can only eat fruit on day one, and so forth. The only real difference is that the emphasis on soup seems to be more prominent on the Cabbage Soup Diet—you’re encouraged to drink several bowls of soup per day.

The Egg Diet: Yet another odd diet with a narrow focus on one particular type of food, the egg diet involves preparing many eggs per day and also eating fruit, toast, and vegetables. There are a few different versions of the egg diet, ranging from a 14-day plan that includes eggs and grapefruit to an egg-only diet that allows nothing but eggs for the duration of the plan.

The Sacred Heart Diet: What is it with the soups? This diet is another on the (apparently) long list of fad diets that include a weight loss soup. On the Sacred Heart Diet, you eat your vegetable-based soup in addition to whichever foods are specified for a particular day.

The 3-Day Military Diet: The 3-Day Military Diet is a classic example of a rapid weight loss scheme that yields no results: It’s extremely short, extremely restrictive, and makes bold claims that aren’t backed by science. It also involves strange food combinations, such as day three’s dinner of 1 cup of tuna, half of a banana, and 1 cup vanilla ice cream.

A Word From Verywell

The GM Diet makes promises that aren’t backed by science. It also lacks many important nutrients, may contribute to disordered eating habits, and doesn’t set you up for a sustainable pattern of healthy eating. Rather, it’s a fad diet that won’t result in long-term weight loss or health benefits. 

Verywell Fit’s mission is to help you reach your health, fitness, and weight loss goals, and part of that is recommending diets that can assist you—and debunking the ones that won’t. 

While choosing a diet is a highly personal decision based on a number of factors, we recommend that you learn about some of the diets we do recommend, all of which contain foods that ensure you get enough vital nutrients, allow for dietary preferences and won’t leave you feeling restricted. 

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