- Reducing calories may be better than fasting for weight loss and promoting health.
- A study on rats found the greatest health benefits in rats that ate just one serving a day.
- But experts warn the studies may not easily be for humans.
A study in rats suggests that reducing your calories and eating them all in one meal may be the best way to live longer and stay slim.
Researchers at the University of Wisconsin said that eating in a calorie deficit was good for health – dieting was even better when compared with fasting.
They observed rodents on four different diets, two that fasted throughout the day and had one large meal for dinner and two that regularly ate smaller meals.
Their study found that rodents in the fasting group that had a 30 percent reduction in calories lived eight months longer than those in the only low-calorie group.
The combination of fasting and dieting also improved insulin sensitivity and reprogrammed the metabolism to focus on using bodyfat as a source of energy.
Lead researcher Professor Dudley Laming said that if this is the main driver of health, the focus should be on diets or medications that focus on fasting rather than on low-calorie diets.
However, one expert noted that the study’s findings may not apply to humans because of the very large biological differences between people and rats.
A study in rats suggests that reducing your calories and eating them all in one meal may be the best way to live longer and stay slim.
The researchers designed four different diets for the mice — which were predominantly males — to follow.
One group ate as much as they wanted, whenever they wanted.
A second group ate a ‘full amount’ but in a shorter period of time – giving them a longer daily fast without reducing calories.
The other two groups were given about 30 percent fewer calories. But one group consumed all of their calories in one sitting—so there was a longer daily fast—while the other ate the same amount but spread out over a day.
The study, which was published in the journal nature metabolism, found rats that consumed their daily calorie intake over a short period of time and then fasted, were healthier and lived longer than rats that ate when they wanted to.
And the rats that only fasted, without reducing their calories, experienced the same benefits of calorie restriction as with fasting.
The livers of the fasting mice also showed hallmarks of a healthy metabolism.
Meanwhile, the rats that ate fewer calories without fasting showed some better blood sugar control, but they also died at a younger age — about eight months earlier than the rats that ate less and fasted.
Professor Lamming said the rats who only reduced their calories had reduced overall health as well as life spans.
He adds: ‘If fasting is the main driver of health, then we should study drugs or dietary interventions that mimic fasting rather than those that mimic low-calorie intakes.’
Professor Sir Stephen O’Rahley, director of the MRC Metabolic Disease Unit at the University of Cambridge, said the findings are interesting but ‘very difficult to extrapolate to humans’.
Because of differences in the speed of the physiological processes of rats and humans, a similar study in humans would require ‘humans to eat all the calories they needed in a single day for a week and then starve for the next 6 days’. said.
Sir Stephen continued: ‘Mice live about two years and we now live to about 80 years, we may have to study it for more than 50 years to test whether our eating habits have changed in such a big way. The change has actually benefited human longevity.
‘It is unlikely that this experiment will ever be done.
‘We know that avoiding or reducing obesity is beneficial to human health.
‘People find different ways to achieve this. Some people may find that reducing the frequency of their meals works for them.’
What should a balanced diet look like?
According to the NHS, meals should be based on potatoes, bread, rice, pasta or other starchy carbohydrates, ideally whole grains.
• Eat at least 5 portions of a variety of fruits and vegetables every day. All fresh, frozen, dried and canned fruits and vegetables count
• Foods based on potatoes, bread, rice, pasta or other starchy carbohydrates, ideally whole grains
• 30 grams of fiber a day: This is the same as eating all of the following: 5 portions of fruits and vegetables, 2 biscuits of whole wheat cereal, 2 thick slices of wholemeal bread and a large baked potato with the skin
• Have some dairy or dairy alternatives (such as soy drinks), choose low-fat and low-sugar options
• Eat some beans, pulses, fish, eggs, meat and other proteins (2 portions of fish per week, one of which should be oily)
• Choose unsaturated oils and spreads and consume them in moderation
• Drink 6-8 cups/glass of water in a day
• Adults should have less than 6 grams of salt and 20 grams of saturated fat per day for women or 30 grams for men
Source: NHS Eatwell Guide
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