Nature Metabolism's surprising study: low-calorie diet alone is not enough

In the past few decades, scientists have discovered that long-term calorie restriction has many benefits for animals: weight loss, better blood sugar control, and even longer lifespan

Researchers largely believe that reducing food intake achieves these benefits by reprogramming the metabolism

As trends such as intermittent fasting continue to dominate, new findings provide support for preliminary evidence that fasting can promote human health

This research further emphasizes the complexity of nutrition and metabolism, and provides guidance for researchers trying to unravel the real reasons why diet is beneficial to animal and human health

Researchers have found that the combination of fasting and eating less can reduce weakness in old age and extend the life of mice

Surprisingly, mice that consumed fewer calories but never fasted died earlier than those that ate as much as they wanted, suggesting that calorie restriction alone may be harmful

The research was published in Nature Metabolism on October 18

Pak and Lamming were inspired to carry out this research because the researchers began to realize that previous studies inadvertently combined calorie restriction with prolonged fasting by providing animals with food only once a day

Lamming has long studied the effects of dietary restriction on metabolism.

To clarify these factors, Lamming's team designed four different diets for mice

People in the other two groups consumed about 30% less calories every day or throughout the day

It turns out that many of the benefits originally thought to be simply calorie restriction—better blood sugar control, healthier use of fat for energy, prevention of aging and longer life—also require fasting

Fasting itself, without reducing food intake, is as effective as calorie restriction during fasting

The researchers did not individually study the effects of fasting on longevity or weakness as mice age, but other studies have shown that fasting can also provide these benefits

Although the mice that did not fast but consumed fewer calories had improved blood sugar control, they also died earlier

"This is quite surprising," Lamming said, although other studies have also shown some negative effects of calorie restriction

The original research was conducted in male mice, but Lamming's laboratory also found a similar effect of fasting on metabolism in female mice
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This research shows that even in a laboratory environment, dietary research is very difficult
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Human research is more difficult, because the level of human control cannot be compared with animal models
.
This new research can provide direction for future research to answer whether fasting can improve human health
.

Lamming said: "We need to know whether people need to fast to see benefits
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" "If fasting is the main driver of health, we should study drugs or dietary interventions that mimic fasting, rather than imitating low-calorie diets
.
"