15lb-A-Week Weight Loss Diet Has No Evidence To Support It | Science Fact Or Fiction?

The GM diet is said to have been developed with help from the US Department of Agriculture and the FDA. The diet was designed as a 7-day very low-calorie diet which consists of mainly non starchy fruits and vegetables. Towards the end of the week, you may include some protein, grains and juices. As with any diet- lots of water is advocated for. The diet claims benefits such as ‘not leaving you feel like you’re starving’, ‘helping you achieve a complete body transformation’, ‘helping you rid your body of toxins’ and the list goes on.  

The diet can supposedly help you lose up to 15lbs (6.8kgs) in just one week, get rid of toxins and impurities in your body, improve your digestion and enhance your body’s ability to burn fat.

But be warned, like the old saying goes – if it sounds too good to be true, it probably is. However, let’s give the GM diet an analysis weighing up the pros and cons, and give our take on it.

Which foods are permitted on the GM diet?

The GM diet plan is broken up into seven days, each with strict rules about which food groups you can and can’t consume. It recommends that you drink 8–12 glasses of water each day to stay hydrated throughout the week. Exercise is optional on the diet; however, it advises against exercise during the first three days. It also allows followers to consume two to three bowls of “GM Wonder Soup” each day. It’s made with cabbage, celery, tomatoes, onions and bell peppers.

Here’s an outline of the diet structure:

Day 1:

  • Fruit only. Eat any kind of fruit except bananas and mangoes

Day 2:

  • Vegetables only, raw or cooked
  • Limit potatoes to your morning meal

Day 3: 

  •  Eat fruit and vegetables of any kind, except bananas
  •  Do not consume potatoes because the carbohydrates will be coming from fruit consumed

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 skimmed milk, but doesn’t ban whole or 2% milk. At lunch, you’ll consume one cup of cabbage soup

Day 5:  

  • You can eat portions of beef, chicken, or fish
  • On this day you can have wonder soup, and power soup

Day 6:

  • Any meat, beef, chicken, or fish, plus unlimited amounts of vegetables, but no potatoes, sweet potatoes, corn or peas

Day 7: 

  • Only brown rice, fruit, fruit juice, and vegetables

Any benefits?

As with all eating plans, it’s important to look at the pros and cons. The GM diet does encourage you to eat lots of fruit and veggies. Fruits and vegetables are low in energy and high in nutrients, which will naturally make you feed full when eating. Of course eating lower calorie foods may enable you to be in a calorie deficit a lot faster than consuming energy dense foods. 

It has an abundance of fibre, Vitamin C, and antioxidants. Eating all those fruits and veggies means you probably won’t have much trouble hitting your fibre goals. It helps you stay hydrated as it encourages many glasses of water per day which is good… I suppose? It has no processed foods. Naturally having fewer amounts of refined carbohydrates and processed foods will be beneficial for our health.


As with most ‘too good to be true diets’ there are drawbacks, and often many of them. Healthy weight loss happens at a rate of  0.5kg (1-2lbs) per week. So the fact that the GM diet promises a loss of 10 to 17lbs (4-8kgs) in the same time-frame is the ultimate red flag for a FAD diet. 

When you restrict your calories to such an extent, our metabolism slows down and your body goes into ‘starvation’ mode which means when you eat ‘normally’ again (which is bound to happen because there’s no way this is sustainable) you will hold onto all the calories in the food to prevent it for the next time you’re wanting to starve your body.

The GM diet can have detrimental effects on your relationship with food and aid the cycle of dieting – which points to the fact that we restrict food intake, binge on those restricted foods because we can’t restrict it anymore and then feel guilty and restrict again. And the cycle continues. Furthermore it categorises foods into good and bad. When we look at food as good or bad , we ultimately paint a picture in our head that the ‘bad’ food should be restricted which leads to us over thinking our food choices. 

The GM diet has no research supports it. There are zero studies that claim the GM diet is actually healthy or good for weight loss.   

We are under nourishing our body by only consuming the foods that the diet says. Protein, Iron , vitamin B12 an many other vitamins and minerals are avoided. These are vital to our bodies health and longevity. If you’re wanting to head into a state of malnourishment. Keep following this restrictive diet.  

The foods on the diet are very low in energy aka calories. Simply put, our bodies need calories (energy) to survive and function. Our brain alone needs glucose to function adequately. Therefor it’s likely that your concentration will decrease as well as your energy levels throughout the day.

The verdict

Quick fixes sound appealing in the short-term but the damage long-term definitely needs to serve as a reminder for those wanting to embark on restrictive eating patterns. While losing a ton of kg’s in one week may seem appealing – you’re almost guaranteed to pack the kilos back on in the weeks to follow. 

Instead of engaging in endless cycles of yo-yo dieting and losing weight only to regain it, try incorporating a lifestyle change into your everyday life. The GM diet in our opinion is not sustainable. Which is the big question you always need to ask yourself when embarking on a weight-loss effort.

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Our articles should be used for informational and educational purposes only and are not intended to be taken as medical advice. If you’re concerned, consult a health professional before taking dietary supplements or introducing any major changes to your diet.

Jenaed Gonçalves Brodell

Jenaed Gonçalves Brodell

Writer and expert

Jenaed Gonçalves Brodell is a well know Registered Dietitian (HCPC) and Sport Scientist. She is a fitness enthusiast and comes from a semi professional field hockey background. Her passion for sports nutrition and background in the sporting arena making her relatable to many amateur and elite sports personnel. She has experience working for the NHS & in South Africa as a consultant dietitian. She provides evidence based, easy to follow, practical advice and guidance.She has experience in the Paediatric field specialising in sports performance for junior and adult athletes. Her writing background comes from extensive researching throughout her career finding the most up to date information and translating it into easy to understand information for the public. She shares information on her public instagram page @the_Athletes_dietitianUK on the latest in evidence based nutrition.

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