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The GM Diet – Everything You Need To Know

Published: 13th May 2018. Last updated: 21th July 2019.

Shaun Ward MSc ANutr

Staff Writer


Introduction

The GM diet is thought to have been created in 1985 for the employees of General Motors, an American multinational corporation.

It is a unique diet that stands out from most others as it follows a system whereby it advises people to have “food-specific” days, focusing on only a couple of major food groups, as opposed to weekly schedules.

This diet plan comes with big claims such as dramatic weight loss in one week, detoxification, and improved digestion.

This has made the diet extremely popular for those wishing to notice significant changes in a very short space of time.

What Is The GM Diet?

The GM diet is mainly focused on encouraging people to eat more fruit and vegetables, in different combinations day-to-day.

Like most diets it also tries to restrict the intake of added sugars, processed foods, and refined carbohydrates, to try and actively lower ones calorie intake.

There is even mention from GM diet experts that it contains "negative-calorie foods" that require more calories to digest compared to the calories in the food itself.

The main concept of the GM diet plan is that it is broken up into 7 separate days, each with strict rules about which food groups you can consume on each day.

Although the diet is essentially just a 1 week plan, it may be repeated multiple times to achieve weight loss that requires longer commitments, however a break of 5-7 days is recommended between cycles.

Alongside the food, the GM diet also states people must drink 8-12 glasses of water every day to ensure adequate hydration (many of the foods in the diet also have a high water content).

Day One – Fruit

  • Eat only fruit (except bananas as they are too high in carbohydrates)
  • There is no limit on the amount of fruit allowed
  • A focus is put on melons as they are low in calories and high in water

Day Two – Vegetables

  • Eat only vegetables (raw or cooked)
  • There is no limit on the amount of vegetables allowed
  • The only restriction is that potatoes are only permitted at the breakfast meal

Day Three – Fruit and Vegetables

  • Eat only fruits and vegetables
  • There is no limit on the amount of fruits or vegetables allowed
  • The only restriction is that bananas and potatoes are ideally avoided

Day Four – Bananas and Milk

  • Eat or drink only bananas and milk.
  • A limit is placed on 6 large, or 8 small bananas, and 3 glasses of skimmed milk (vegans can swap to soy milk)

Day Five – Meat

  • Eat 2 portions of beef, chicken or fish (500 grams total per day)
  • Alongside this, people can eat 6 whole tomatoes
  • Vegetarians may replace meat with either brown rice or cottage cheese
  • Water consumption should increase by 2 glasses to help flush out the extra uric acid (a breakdown product of purines found in meat)

Day Six – Meat and vegetables

  • Eat 2 portions of beef, chicken or fish (500 grams total per day)
  • Vegetables can be eaten on this day, but potatoes are to be avoided
  • Vegetarians may replace meat with either brown rice or cottage cheese
  • Water consumption should increase by 2 glasses to help flush out the extra uric acid (a breakdown product of purines found in meat)

Day Seven – Rice, Fruit, and vegetables

  • Eat only brown rice, fruits, fruit juice and vegetables.
  • There is no limit on the amount of rice, fruits, fruit juices, or vegetables allowed

In terms of other drinks that can be consumed on the diet, natural sweeteners are allowed, but soda, alcohol and other non-diet beverages are not allowed.

As a final point, in the breaks between the GM diet weeks, or once an individual has chosen to stop the diet altogether, a a high-protein, low-carbohydrate diet is recommended to help maintain results.

The Positives of The GM Diet

Below we've listed everything we personally believe to be a positive:

It Can Support Weight Loss

The GM Diet is certainly able to achieve its main goal and successfully induce weight loss in the vast amount of people on the diet.

However, it does not cause weight loss due to any type of “special” methods that are unseen in other more well-balanced diets.

Weight loss on the GM diet acts just like any other diet that causes weight loss – by directly or indirectly creating a caloric deficit (consuming less calories than one expends per day).

The focus on predominantly fruit and vegetables on the GM diet, to create that caloric deficit, is also a dietary principle that is consistently associated with weight loss [1] [2].

It is important to note that weight loss on the GM diet has not been proven in scientific research, but based on the significant dietary restrictions and estimated daily caloric intakes, it is logical to assume this is a probable outcome.

Other User-Reported Benefits

The below benefits are based on user reviews as opposed to scientific data:

  • Improved quality and appearance of the skin
  • Enhanced mood
  • Better digestion
  • Detoxification
  • Improving symptoms of irritable bowel syndrome and constipation

Similarly, far more conclusive scientific research is also needed to truly justify these subjective reports.

The Negatives of The GM Diet

Below we have listed everything we believe to be a drawback:

No Scientific Research

The biggest drawback of the GM diet is that there is no research that evaluates how well it works.

Most of the results given by advocates of the diet are purely based on anecdotal evidence, which although interesting, is not reliable evidence.

Although the fundamental concepts of the diet for inducing a caloric deficit are sound, many of their claims are not supported by the scientific literature. For example:

  • “The GM diet includes negative-calorie foods” – A negative calorie food implies that the calories required to digest a given food exceeds the amount of calories that the food contains. However, there is no evidence to support such a claim, and no true “negative calorie” food is thought to exist.
  • “The GM diet detoxifies the body” – As no research exists on the diet, this claim cannot be justified. Not only this, but the claim that any diet can detoxify the body is heavily debated by scientific researchers. For the most part the bodies major organs, such as the kidneys, have functions which neutralize and excrete any potential toxins in the body.

Lacks Balance & Consistency

A truly well-balanced diet involves the daily consumption of multiple key food groups which all provide their own group of essential nutrients.

As the GM diet primarily focuses on just 1-2 food groups per day, by definition it is an unbalanced diet that may result in micronutrient deficiencies and strong feelings of deprivation.

In fact, it is technically possible for this diet to cause deficiencies in almost nutrient, with the main concerns being dietary fat, protein, vitamin B12, iron, and calcium.

As micronutrients are essential to sustain life and for optimal physiological function, reducing dietary intake could lead to poor growth, intellectual impairments, and increased risks of illness, infection, and disease.

The diets relatively low protein intake will also make it hard for individuals to feel satiated on the diet which could impact its long-term sustainability [3]. After all, a lot of research has demonstrated that the number 1 determinant of diet success is long-term consistency [4].

Conclusion

The GM diet is broken up into 7 separate days, each day with its own strict rules about which food groups to eat or avoid.

As it places limits on high-calorie processed foods, it should effectively cause weight loss whilst improving mood and digestion.

However, changing between food groups each day is highly unnecessary and may cause nutrient deficiencies and issues with diet sustainability.

People would be better off sticking to more well-balanced, simpler diets that are also able to achieve significant weight loss.

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