The GM diet plan promises followers that they can lose up to 15 pounds in one week by eating a different food or food group each day for a total of 7 days.
Proponents of this plan claim that the GM diet not only helps you lose weight but also rids the body of toxins, improves digestion, and boosts energy levels, mood, and well being.
Can a diet really accomplish this in 7 days?
The following article will provide an overview of the GM diet and discuss whether this plan can deliver on its many promises.
What Is the GM Diet Plan?
The GM diet stands for General Motors diet.
As the story goes, the GM diet was developed in 1985 by the General Motors Corporation.
It was intended to be a workplace wellness program that would help GM employees lose weight and improve efficiency.
According to the GM Diet History website, this weight loss program was developed with support from the Food and Drug Administration (FDA), and testing was conducted by the Johns Hopkins Research Center (1).
However, this origin story is a myth (2), and the true beginnings of the GM diet remain unknown.
Foods Allowed on the Diet
The GM diet follows a 7-day plan where participants eat a different food group or combination of food groups each day.
For example, on day one, you eat only fruits (except bananas), and on the seventh day, you eat a mixture of brown rice, fruits, and vegetables.
Foods included in this program are fruits, vegetables, brown rice, meat, and dairy.
Additionally, followers of this plan also consume the GM diet soup, sometimes referred to as “wonder soup.”
It is a low-calorie, vegetable soup that consists of cabbage, carrots, tomatoes, celery, and pepper.
Proponents recommend consuming 2 to 3 bowls of wonder soup throughout the day to help curb hunger pangs.
Below is a summary of the GM diet, with example menu plans:
7-Day GM Diet Meal Plan
Day 1 – Fruits
On day 1, you eat only fruit except for bananas, with an emphasis on melons and citrus fruits.
There is no limitation on the number of fruits that you can eat on this day.
- Breakfast – Bowl of mixed berries
- Snack – 1 orange
- Lunch – Grilled watermelon slices
- Snack – Oven-roasted apple
- Dinner – Cantaloupe and pineapple slices
Day 2 – Vegetables
For day 2, you limit your intake to vegetables. Potatoes and sweet potatoes are allowed but only for breakfast.
Similar to the first day, there is no limitation on the portions of veggies that you eat, and they can be enjoyed either raw or cooked.
Vegetables that can be eaten on the GM diet include bell peppers, cherry tomatoes, onions, spinach, sprouts, kale, cucumbers, and mushrooms, to name a few.
- Breakfast- Oven-roasted bell pepper, onion, and sweet potato medley
- Snack- 1 cup of cabbage soup
- Lunch- Broccoli “steaks”
- Dinner- Steamed asparagus over a bed of lettuce
Day 3 – Fruits and Vegetables
On day 3, you enjoy a combination of foods from the first two days, except for bananas and potatoes.
- Breakfast – Avocado slices topped with strawberries and mango
- Snack- 1 grapefruit
- Lunch- Mixed greens with mandarin oranges and apples
- Dinner- Cherry tomatoes, grapes, asparagus, and cucumber slices
Day 4 – Bananas and Milk
Your meals on day 4 consist of only bananas and milk, preferably skim milk.
Vegetarians can opt for unsweetened soy milk.
Be sure to restrict intake to six large bananas and three glasses of milk. Day 4 is widely acknowledged as being the most challenging day.
- Breakfast- Smoothie prepared with 2 bananas and 1 glass of milk
- Snack- Banana with a bowl of wonder soup
- Lunch- Banana with 1 glass of milk
- Dinner- Smoothie made with 2 bananas and 1 glass of milk
Day 5 – Meat
For non-vegetarians, intake on diet day 5 consists of 20 ounces of beef, chicken, or fish, divided between two meals.
In addition to meat, you also eat six tomatoes, which adds fiber to the meal plan.
Vegetarians can substitute brown rice or cottage cheese in place of meat.
Proponents of this diet also recommend increasing water intake by an extra two glasses on this day to help flush uric acid from the body.
Uric acid is a metabolic by-product resulting from the breakdown of purines, which are compounds found in meat.
- Breakfast- Two tomatoes
- Snack- Wonder soup with two tomatoes
- Lunch- 10 oz. grilled chicken breast with tomato slices and an extra glass of water
- Dinner- 10 oz. pan-seared salmon topped with diced tomato and an extra glass of water
Day 6 – Vegetables and Meats
Day 6 consists of 20 ounces of meat with unlimited vegetables, except for potatoes and tomatoes.
Again, the vegetarian option is either brown rice or cottage cheese.
- Breakfast- Tropical fruit salad with papaya and mangoes
- Snack- Baby carrots
- Lunch- 10 oz. grilled shrimp with arugula salad
- Dinner- 10 oz. baked chicken thighs with roasted vegetables
Day 7 – Brown Rice, Fruits, and Vegetables
On day 7, the final GM diet day, you eat brown rice, fruits, and vegetables. No-added sugar fruit juices are also permitted on this day.
- Breakfast- Banana, strawberry smoothie made with 100% pomegranate fruit juice
- Snack- Brown rice and a boiled potato
- Lunch- Mashed avocado with diced tomatoes
- Dinner- Brown rice with steamed broccoli and a splash of lemon juice
GM Diet Guidelines
Followers of the GM diet plan are encouraged to drink 8 to 12 glasses of water per day to prevent dehydration and to help promote digestion and bowel movement.
Black coffee and tea, including green tea, are permitted as part of this diet, as long as they are unsweetened.
Food items that are not allowed on this diet include:
- Sugar-sweetened beverages and junk food, such as soda and cookies
- White rice
- Foods high in processed carbs such as bread and pasta
- Beans and legumes, such as kidney beans and lentils
Exercise is optional while GM dieting, although followers are encouraged to avoid intense physical activity during the first three days.
Finally, followers of this diet can repeat the 7-day cycle until they have achieved their weight loss goals.
However, it is recommended to wait for 8 to 10 days between cycles to avoid nutritional deficiencies.
Does the GM Diet Really Work?
The GM diet will likely result in short-term weight loss for most individuals, mainly because this diet lowers daily calorie intake and creates a calorie deficit.
A calorie deficit occurs when you consume fewer calories per day than you burn.
This plan creates a calorie deficit in several ways, including by:
- Increasing fruit and vegetables in the diet, which are healthy foods that are generally low in calories
- Not allowing added sugars or processed foods
- Eliminating food groups from the menu on specific days
One way that the GM plan helps you lose weight is by encouraging intake of whole, unprocessed foods with plenty of fruits and vegetables.
Additionally, many of the foods in this plan, such as fruits, vegetables, and soups, have higher water content, which may increase feelings of fullness, thereby reducing daily food intake (3).
How Much Weight Can You Lose on the GM Diet?
According to proponents of this plan, you can lose up to 15 pounds in one week while following the GM diet. However, there are no studies to back this claim.
The amount of body weight that a person can lose on any diet depends on several factors, including age, gender, genetics, starting weight, and extent of calorie restriction.
Additionally, when you lose weight rapidly, some of that loss will be from water weight and muscle loss instead of body fat.
This is because anytime that you reduce your calorie intake, the body looks for alternative sources of energy.
Initially, the body turns to glycogen, which is a type of energy reserve stored in muscles and the liver.
Glycogen is known to hold onto water molecules; therefore, as glycogen is burned for fuel, water is excreted from the body and may give the impression of rapid weight loss.
However, this water loss is only temporary, and you will likely regain it once you resume a regular diet.
During weight loss, the body also turns to muscle mass for energy in addition to fat stores.
Research has shown that eating enough protein during a diet may help reduce the loss of muscle tissues (4-7).
However, dietary protein is lacking on the GM diet, especially during the first three days, which could lead to excess muscle loss.
Therefore, the better question to ask is, should you lose 15 pounds in 7 days?
Most health experts and dietitians agree that a more realistic weight loss goal is around 1 to 2 pounds per week while dieting (8), with an understanding that weight loss may be more rapid at the start of a diet and will slow down as you near your goal weight.
Risks and Side Effects of the GM Diet Plan
While the promise of rapid weight loss in seven days may sound appealing, the GM diet has many disadvantages that you should be aware of before trying this diet plan.
There Is No Scientific Evidence to Support the GM Diet
First, there is little, credible information concerning this diet, and much of the available information is anecdotal.
Without high-quality human trials, it is difficult to compare the efficacy and safety of the GM diet to other diet plans.
Lacks Essential Nutrients
Perhaps the biggest drawback of the GM diet is that it is unbalanced and does not meet nutritional requirements.
At its core, the GM diet eliminates food groups on certain days, resulting in an eating pattern with variable micro-and macronutrients.
For example, the first three days of this diet focuses on consuming only fruits and vegetables, which are low in proteins and heart-healthy unsaturated fats.
This approach may be counterintuitive as research suggests that high-protein dietary plans may help reduce appetite and promote weight loss (9).
Additionally, many healthy foods are excluded from this plan, including heart-healthy oils, such as olive oil, as well as eggs and nuts.
Individuals on the GM diet may not be getting enough protein, unsaturated fat, vitamin B12, iron, calcium, magnesium, and zinc in their diets, especially during the first three days.
Could Result in Yo-Yo Dieting and Weight Gain
The GM diet is meant to be a short-term, 7-day program.
One of the problems with these “quick fix” diets is that you may regain weight once you stop following the meal plan.
This could lead to a never-ending cycle of dieting, losing weight, regaining it, and then dieting again- sometimes referred to as yo-yo dieting.
Research has linked yo-yo dieting to multiple adverse health problems, including increased appetite, greater weight gain over time, and increased body fat (10-12).
For example, one review study found that people on short-term diets regained 30 to 65% of the weight that they had lost within one year(10).
In a different review article, 11 out of 19 studies determined that a history of yo-yo dieting was associated with higher percentages of body fat and greater amounts of belly fat (11).
Additionally, 4 out of 8 articles in this review reported that yo-yo dieting was linked to an increased likelihood of future weight gain, suggesting that dieters may be prone to gaining more weight than they initially lost (11).
Overall, the drawbacks of the GM diet appear to exceed any advantages.
The health benefits of this plan may include eating more fruits and vegetables while limiting processed foods. However, many other diets also focus on consuming whole foods in addition to encouraging long-term lifestyle change.
Additionally, the GM diet plan promotes rapid weight loss, mostly in the form of water loss, which could result in yo-yo dieting.
Individuals who are interested in long-term weight management may want to avoid this fad diet.
Instead, try focusing on healthy habits that will set you up for long-term success.
A good place to start is by cutting back on processed foods and sugar, eating more fruits and vegetables, establishing an exercise routine, and getting enough sleep.
- “GM Diet History.” GM Diet Works, www.gmdietworks.com/gm-diet-history.
- Cohen, Roger. The General Motors Diet, 29 July 2009, www.nytimes.com/2009/07/30/opinion/30iht-edcohen.html.
- Davy, Brenda M., et al. “Water Consumption Reduces Energy Intake at a Breakfast Meal in Obese Older Adults.” Journal of the American Dietetic Association, vol. 108, no. 7, 2008, pp. 1236–1239., doi:10.1016/j.jada.2008.04.013
- Berentzen, Tina, and Thorkild I A Sørensen. “Effects of intended weight loss on morbidity and mortality: possible explanations of controversial results.” Nutrition reviews vol. 64,11 (2006):502-7. doi:10.1111/j.1753-4887.2006.tb00183.x
- Mojtahedi, Mina C et al. “The effects of a higher protein intake during energy restriction on changes in body composition and physical function in older women.” The journals of gerontology. Series A, Biological sciences and medical sciences vol. 66,11 (2011): 1218-25. doi:10.1093/gerona/glr120
- Evans, Ellen M et al. “Effects of protein intake and gender on body composition changes: a randomized clinical weight loss trial.” Nutrition & metabolism vol. 9,1 55. 12 Jun. 2012, doi:10.1186/1743-7075-9-55
- Pasiakos, Stefan M et al. “Optimized dietary strategies to protect skeletal muscle mass during periods of unavoidable energy deficit.” FASEB journal : official publication of the Federation of American Societies for Experimental Biology vol. 29,4 (2015): 1136-42. doi:10.1096/fj.14-266890
- “Losing Weight.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 4 Feb. 2020, www.cdc.gov/healthyweight/losing_weight/index.html.
- Paddon-Jones, Douglas et al. “Protein, weight management, and satiety.” The American journal of clinical nutrition vol. 87,5 (2008): 1558S-1561S. doi:10.1093/ajcn/87.5.1558S
- Dulloo, A G, and J-P Montani. “Pathways from dieting to weight regain, to obesity and to the metabolic syndrome: an overview.” Obesity reviews : an official journal of the International Association for the Study of Obesity vol. 16 Suppl 1 (2015): 1-6. doi:10.1111/obr.12250
- Mackie, Grace M et al. “Does weight cycling promote obesity and metabolic risk factors?.” Obesity research & clinical practice vol. 11,2 (2017): 131-139. doi:10.1016/j.orcp.2016.10.284
- Dulloo, A G et al. “How dieting makes the lean fatter: from a perspective of body composition autoregulation through adipostats and proteinstats awaiting discovery.” Obesity reviews : an official journal of the International Association for the Study of Obesity vol. 16 Suppl 1 (2015): 25-35. doi:10.1111/obr.12253