A new study shows that simply replacing refined flours with whole grains increases basal metabolism and promotes weight loss. In their whole form, cereals are excellent foods, not only as a source of energy (the sugar from starch), but also because of their high fiber, vitamin and mineral content from the bran and germ.
A large number of studies have also shown that regular consumption of whole grains has a very positive effect on health, in particular on the risk of cardiovascular disease, type 2 diabetes and certain cancers.
These preventive effects translate into significant reductions in premature mortality, whether from cardiovascular diseases (20% to 30% reduction), cancer (14% to 18% reduction) or mortality in general ( 19% to 22% off).
In other words, one of the simplest ways to improve our health and live longer is to simply incorporate whole grains into your eating habits.
Unfortunately, it is estimated that less than 5% of the population eats the recommended three servings of whole grains. At present, the vast majority of cereal products consumed daily (bread, pasta, pastries, etc.) are made from refined white flour, that is to say flour whose bran and germ have been eliminated.
These foods contain only starch, are devoid of fiber, and therefore their nutritional quality has nothing to do with products made from whole grains.
Less stored energy
Some studies have also observed that people who consume the recommended amounts of whole grains (3 servings or 48 g per day) have a lower body mass index and a lower tendency to accumulate fat. Several factors have been proposed to explain this phenomenon (better satiety and more stable blood sugar, among others), but the exact mechanisms remain poorly understood.
To better understand the effect of whole grains on body weight, a research team from Tufts University (Boston, MA) recruited 81 volunteers between the ages of 40 and 65 and randomly separated them into two groups: the the first was fed a diet containing whole grains (and therefore fiber), while the other was fed an identical diet, except that the whole grains had been replaced by refined flours (and therefore devoid of fiber) .
To ensure participants adhered to both diets, the investigators provided all food to both groups free of charge for six weeks.
Lose 2.5 kg by eating whole foods
The researchers made the astonishing observation that the group of volunteers who had ingested whole grains had a significantly increased resting metabolism (43 kcal/day) compared to those who had eaten refined flour products.
They also noticed that whole grain consumers had more abundant stools and that these contained much more energy (57 kcal/day). Taken together, these effects result in an energy loss of around 100 kcal/day, the equivalent of a 30-minute brisk walk.
If we extrapolate this energy deficit over one year, this represents a weight loss of about 2.5 kg, which is similar to what was observed by Harvard researchers during an epidemiological study on the factors responsible for variations in the body weight of more than 100,000 people.
Whether it is to prevent the development of several chronic diseases or to maintain a normal body weight, whole grains are therefore truly foods that we should all favor on a daily basis.
Karl JP et al. Substituting whole grains for refined grains in a 6-wk randomized trial favorably affects energy-balance metrics in healthy men and postmenopausal women. Am. J. Clin. Nutr. 2017; 105: 589-599.
Mozaffarian D et al. Changes in diet and lifestyle and long-term weight gain in women and men. N.Engl. J.Med. 2011; 364: 2392-404
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