Eating whole grains loses 100 calories a day

Eating whole or whole grains instead of refined or white grains increases calorie loss and speeds up metabolism. A study which notably makes it possible to quantify the diet based on whole grains was published in the specialized journal American Journal of Clinical Nutrition. Participants lost up to 100 more calories per day by eating a whole grain diet.

Whole grains, more fiber

Cereals are an important food group for mankind which especially include wheat, rice, oats and barley. Whole grains include the outer nutrient layer of the grains, such as in brown (whole) rice or whole wheat flour. Refined, not whole, grains are starch-based and have been processed as well as broken down into a finer texture, primarily to increase shelf life. This process, known as milling, separates the starch from the dietary fibre, iron and B vitamins. Through an enrichment process, iron and B vitamins can be added later, but generally not dietary fiber. White flour, white bread, and white rice are examples of refined grains.

Effective in weight loss?

Epidemiological studies have suggested health benefits of whole grains and high dietary fiber intake on glycemic control and insulin sensitivity.

This new study which lasted 6 weeks could explain how the consumption of whole grains is favorable for weight loss. Fiber consumption helps to age well. Several previous studies have suggested health benefits of consuming whole grains and dietary fiber in several risk diseases. This study helps quantify how much whole grain and fiber works for weight management, and lends credence to previous studies showing the link between increased whole grain and fiber intake and decreased body weight and better health.

People who followed a whole-grain diet, which meets the recommended dietary fiber intake, lost almost 100 more calories per day due to a combination of increased resting metabolism and greater faecal losses, compared to people who ate refined grains (eg white flour), that is to say with little fiber.

Equivalent to a 30-minute brisk walk

In the study, the calories lost more than usual in those consuming whole grains was the equivalent of a brisk walk for 30 minutes, or eating an extra cookie each day, in terms of impact.

Study in detail

The research team conducted a randomized, single-blind, comparative study over a period of 6 weeks. 81 men and women aged between 40 and 65 took part in this research work. During the first 2 weeks of the study, all participants received the same type of diet and the calorie requirement was calculated for each participant. After 2 weeks, participants were randomly assigned to follow a diet that included a whole-grain or non-whole-grain (refined) diet. The differences between these 2 diets were mainly related to calorie, fiber and macronutrient content. Participants had to eat only the food provided by the team of scientists as well as return the uneaten food. They also had to continue to follow their habits in the eventual practice of physical exercise.

85g of whole grains per day for women, 113 for men

During the 6 weeks, the researchers measured weight, metabolic rate, blood sugar, calories in feces, hunger and satiety. At the end of the study, those who ate whole grains showed an increase in resting metabolic rate and faecal energy loss, compared to those who ate refined grains. The extra faecal loss was not due to extra fiber intake but because of the effect fiber has on the digestion of calories from other foods.

The scientists also note that commercial products made from whole grain flour were also used in this study. The recommended daily intake of whole grains is at least 85g of whole grains for women and approx. 113 g for men. This corresponds to eating between 1.5 and 2 cups of brown rice or oats per day.


Substituting whole grains for refined grains in 6-week randomized trial favorably affects energy balance parameters in healthy men and post-menopausal women. American Journal of Clinical Nutrition. DOI: 10.3945/ajcn.116.139683.

* Presse Santé strives to transmit health knowledge in a language accessible to all. In NO CASE, the information given can not replace the advice of a health professional.

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