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Are all weight loss diets created equal?

School Of Nutrition Posted Sep 08, 2014 Future Fit Training

Would you like to join a weight loss programme but don’t know which one will help you achieve the greatest weight loss?

Are all weight loss diets created equal?

According to a recent review of popular diet programmes, published in the Journal of the American Medical Association, brand names don’t make much difference. Lead author Bradley C. Johnston [1], stated that low-carb or low-fat diets resulted in the most weight loss; however, despite a difference of a few pounds between groups, all the programmes in the study were equally effective.

The review included 48 randomized controlled trials that tested 11 popular branded diets for at least three months. All of the participants were overweight or obese, and they all had daily nutrient or calorie targets. Some had exercise goals as well.

The low-carb diets, like Atkins, South Beach and Zone, require that no more than 40 percent of daily calories come from carbohydrates and another 30 percent come from protein.

The low-fat diets, including the Ornish and Rosemary Conley diets, specify that 60 percent of calories come from carbohydrates and less than 20 percent come from fat.

Johnston and his team also included trials of moderate macronutrient diets, like Weight Watchers, Biggest Loser, Jenny Craig, Volumetrics and Nutrisystem. These diets also require around 60 percent of calories from carbohydrates but allow more from fat and less from protein than the low-fat diets studied.

Results showed that, compared to no diet at all, each of the diets produced more weight loss, which is expected. But the most successful were the low-fat and low-carb diets. At the six-month point, people on low-carb diets had lost an average of 8.73Kg, which dropped to 7.25Kg at one year. Low-fat dieters lost an average of 7.99Kg by six months, which also dropped to 7.27Kg by one year. On the other hand, moderate macronutrient dieters lost an average of only 5.67Kg after one year.

Furthermore, the different diet brands within each category didn’t make much difference. For example, among the low-carb diets, the Atkins diet resulted in only 1.71 kg greater weight loss than the Zone diet at the six-month point.

The Bottom Line

When you follow a diet programme, you are making a lot of significant changes to your usual diet. For example, just by reducing or cutting out junk food, you will be significantly reducing your intake of junk calories, which are usually the biggest contributors to weight gain. Therefore, you should see some weight loss with any diet programme. 

There may be some advantages, however, to choosing branded diet programmes. Branded diets often involve a comprehensive programme which includes behavioural support and exercise, so they are more likely to be effective. Some may also include prepared foods, recipes and meal ideas, all of which can be helpful aids for dieters.

Having said that, you should choose a diet which fits in with your lifestyle and eating habits, regardless of whether the diet is branded or not. Although the moderate macronutrient diets in this review study resulted in slightly less weight loss than the others, they tend to offer the greatest variety of foods and so can offer more flexibility in that respect. Because of this, this type of diet may be the best choice for most people.  

We know that it is possible to achieve weight loss with more than one type of diet. But at the end of the day, perhaps the best diet for you to follow is the one that you are most likely to stick to!

You can learn more about weight loss diets on our interactive online Nutrition and Weight Management course here.

Written by Victoria Trowse 


1. Johnston, BC, et al. (2014). Comparison of Weight Loss Among Named Diet Programs in Overweight and Obese Adults, :  A Meta-analysis. JAMA 312 (9): 923-933.

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