dieta jejum

A new international diet sensation: intermittent fasting

Endocrinology, Gastroenterology

Dr. Mark Mattson, chief of the neuroscience laboratory at the National Institute of Aging in Baltimore, Maryland (USA), who has been researching the effects of fasting for the past fifteen years states that “From an evolutionary perspective, intermittent fasting is normal, and eating 3 meals a day plus snacks is abnormal”.

There have been various animal research studies strongly suggesting that animals age slower, and live longer, if they decrease their daily food intake over a number of years. This research has stimulated other studies attempting to see if fasting on an occasional basis can be beneficial for humans, and the results have been positive.

Somewhat like the way weight lifting puts the body under a stress that results in stronger muscles, fasting seems to put the body under a stress that makes the brain function better. When the brain senses that we are in a period of fasting, it secretes chemicals that are “neurotropic”; that is, they stimulate the growth of new brain cells.

Studies done by Dr. Matteson and colleagues have shown that rats with an Alzheimer-type condition who fast every other day stabilize or even show reversal of some of the effects of their neurological condition, and they also show a lower index of body fat than rats put on a standard diet

Studies suggesting the benefits of fasting and calorie restriction in animals has led to the popularization in the last few years in the United States and Europe a number of different diet plans for humans to help them lose weight and hopefully provide some other benefits for metabolism and the brain.

The intermittent fasting diets fall into three main categories:

1) Alternate Day Fasting, where a person’s diet alternates from a day of normal eating with a day of relative fasting (days in which the person takes in a limited number of calories, about 500 or 600 calories—about a quarter of a person’s normal intake);

2) The 5:2 Diet, where a person eats normally five days a week but two days a week they eat 500 calories for a woman, and 600 calories for a man, and;

3) The 8-Hour Diet, in which a person confines their eating to an 8-hour period each day, and for the remainder 16 hours of the day, they take in no calories.

So far there have been not enough studies done in humans to determine which of these diets might give the best results for losing weight, improving your sugar metabolism or possibly improving mental functioning, so there are still no conclusions which of these diets might be best. It seems though that the 5:2 diet is easier for people to adhere to than alternate day fasting.

The major conclusion from the research on fasting is that, especially if done on an occasional basis, going without food for extended periods might well be beneficial for your body in several ways, beyond losing some weight. Even 16 hours without caloric intake seems to be enough “stress” to induce your organism to make changes that make it work better.

Of course you don’t have to try one of these three diets if you want to experiment with fasting. You could try, one or two days a week, going without food (only consuming water, coffee, or tea) for about 16 hours. You could start your “fast” after dinner, then not have solid foods until the next afternoon. If you have any medical condition, check with your doctor first if this would be OK for you, and when there is more data about fasting, we will let you know here in Mais Saúde.

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See also in ProcuraMed:

Exercise and memory


Esta postagem também está disponível em: Portuguese (Brazil)

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