By cutting down on your daily calorie intake once and for all, you can seriously change your life for the better, according to several scientific studies.
Let's imagine such a scene from the near future. A restaurant. A man and a woman on a first date. When you finally manage to deal with some of the nervousness, everything goes well.
The man says that he is 33 years old, he has not yet been married and, apparently, is not averse to finally starting a family.
The woman tells him the story of her life: she is 52, she was married, divorced, and she has children who are already over 20.
The man is surprised: the woman does not look older than himself, or even younger.
Such a scene is a dream come true for Julie Mattison of the US National Institute of Aging (NIA). As she suggests, the time will come when a person's biological clock will count down completely different years that are now called age.
Now this sounds unlikely, but thanks to the advances in medicine and the general improvement in living conditions, humanity has already taken quite a few steps towards this goal.
For example, in 2014 in the United States, according to a statistical report (United States Health Interview Survey), 16% of Americans between the ages of 50 and 64 suffered from chronic diseases every day. And just three decades ago there were 23%.
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In other words, we not only live longer, but also, compared to our ancestors, healthier in the last phase of our lives. Moreover, achieving the latter seems to be easier than trying to increase life expectancy.
So what do we need to do to increase the duration and quality of life even more? Researchers around the world have a wide variety of ideas on this subject.
However, for Matthison and her colleagues, the answer is: make very simple changes to your diet. According to them, the main thing is to reduce the amount of food on your plate, what scientists call "calorie restriction."
The proposed diet is not limited to simple rejection of fatty foods or periods of self-restraint. The point is that gradually and carefully reduce the portions of the normally eaten food and never increase them again.
Studies dating back to the early 1930s have shown that a 30% decrease in the amount of food eaten each day leads to a longer and more active life - however, in worms, flies, rats, mice and monkeys.
In general, it is well established that in the animal kingdom, restricting calories is the best cure for the devastating effects of age on the body. Perhaps the same could work in humans as well?
Back in ancient Greece, Hippocrates, being one of the first doctors who considered illness to be a completely natural thing, noticed that many diseases are associated with gluttony. Obese Greeks died younger than skinny Greeks - this was obvious.
At the end of the 15th century, the feeble Venetian aristocrat Luigi Cornaro managed to do the seemingly impossible to himself. If self-indulgence is only harmful to health, then perhaps asceticism will be useful?
Cornaro, who was 40, only started eating 350 grams of food a day (roughly 1,000 calories by current estimates). He ate bread, eggs and broth. From the meat he chose veal, goat, beef, partridge, thrush and chicken. From fishermen he bought fish caught in local rivers.
Thus, by limiting himself only in the quantity, but not in the variety of food, Cornaro, he said, achieved perfect health. He lived for another 40 years.
Although at the end of his life he claimed to be 98, it is believed that he was 84 when he died - and this is a very impressive age for the 16th century, when 50-60 years old were considered old.
In 1591, his grandson published his grandfather's posthumous essay in three volumes entitled Discussions on Sober Living, in which Cornaro insisted on introducing calorie restriction in the daily life of all people in order to change the aging process and give older people the opportunity to lead a fulfilling life. for the good of society.
Life Extension Experiments
Cornaro was, of course, an interesting person, but his statements are not enough for serious science to come to the same conclusions. Even if he did feel great during the nearly 50 years that he limited himself to food (which is very doubtful), his case is just the story of one person.
In 1935, a fundamental study on white rats showed that dietary restrictions by 30-50% led to an increase in life expectancy and delayed death from age-related diseases.
Of course, what's good for a rat and any other laboratory animal doesn't necessarily work for humans.
Long-term studies, where people are observed throughout life, are rare. “It’s hard for me to imagine that someone would finance a program like this,” says Matthison. "Even if you start your research at the age of 40 or 50, you still have 40 years ahead of you."
In addition, she adds, in our complex society, it is almost impossible to exclude the influence of additional factors - exercise, smoking, treatment, mental illness, etc.
So in the late 1980s, it was decided to conduct two independent long-term studies on the effect of calorie restriction, one at the National Institute of Aging and the other at the University of Wisconsin. Rhesus monkeys were selected as test subjects.
The fact is that humans with these primates have 93% of their total DNA. And we are aging very similarly.
In rhesus monkeys, after they overcome the middle age barrier (for them it is about 15 years old), the back begins to hunch, the skin and muscles begin to grow decrepit, and the coat turns gray. What's more, like humans, these primates have an increasing incidence of cancer, diabetes, and heart disease with age.
“They are a great model for aging research,” says Rosalyn Anderson, a gerontologist at the University of Wisconsin.
Plus, they're easy to keep under control. A diet has been developed for 76 rhesus monkeys at the University of Wisconsin and 121 at the NIA. They are fed special cookies in which the primates receive all the nutrients and minerals they need. At the same time, half of the macaques included in the restriction group eat 30% less.
None of them are starving. Take Sherman, a 43-year-old male from the NIA lab. Since the 16-year-old Sherman was "enrolled" in the calorie restriction (CR) group in 1987, Mattison said he has not shown any signs or effects of hunger.
Sherman is the oldest rhesus monkey we know of. He has already lived 20 years longer than the average captive primate. Younger primates fell ill and died, and he seemed not subject to aging. Even 10 years ago, he (by age) could be ranked among the old macaques, but even now he does not look old at all - both in behavior and appearance.
The same - of course, to varying degrees - applies to the rest of the test subjects in the laboratories of the National Institute of Aging. “We have fewer cases of diabetes and cancer in the calorie-restricted group,” notes Matthison.
In 2009, researchers at the University of Wisconsin published a report with equally impressive results: their food-restricted macaques looked younger than their peers, their coats were brown instead of gray. Their body was healthier, without internal pathologies typical of age.
Oncology cases - for example, adenocarcinomas - were reduced by more than 50%. The risk of heart disease has also been cut in half.
Indian macaque
And while macaques that ate ad libitum developed diabetes or were in a pre-diabetic state, none of the restricted primates showed any signs of diabetes in their blood.
Overall, in 20 years, only 13% of the monkeys in the CR groups have died of age related causes. In the “as much as you like” group, 37% died from such reasons - almost three times more. In a more recent report from the University of Wisconsin from 2014, this percentage has not changed.
“We have demonstrated in primates that aging can be controlled,” Anderson notes. "And that means aging in itself is a perfectly valid target for clinical intervention and care."
In other words, if aging can be postponed, then this applies to all diseases associated with it.
Reducing the amount of food we eat has certainly had a positive effect on primates. However, it will be much more difficult for a person to comply with such restrictions. To begin with, high-calorie food lies in wait for the modern person literally everywhere. In addition, for some people, gaining excess weight is quite natural, as they are arranged.
"There is a big genetic component to this, and for some it is very difficult to stay thin," Anderson notes. - We all know people who, without any damage to their bodies, can eat a whole cake at a time. But there are others who only need to eat one cake and already have to buy larger jeans."
It would be ideal if the amount and type of food we eat were adapted to who we are - with a genetic predisposition to gain weight, with our metabolism and other physiological traits inherent in us.
However, a predisposition to be overweight is not necessarily a sentence, but rather an indication of the choice we face in life. “The genetic history of my entire family suggests that I am prone to fatness,” said Susan Roberts, a nutritional scientist at Tufts University in Boston. "So I'm using a flexible form of calorie restriction."
"I try to keep my BMI (body mass index) around 22. I figured that for this I need to eat 80% of the amount of food that I would eat if my BMI was 30, like the rest of my family." …
Roberts emphasizes that this is not difficult - the iDiet program helps her to control her weight and at the same time not feel hungry. I would not comply with these restrictions if it was uncomfortable for me, she emphasizes.
Roberts knows the benefits of calorie restriction firsthand. For more than 10 years she has led the study, which is abbreviated as Calerie (Comprehensive Assessment of Long-Term Effects of Reducing Intake of Energy - "Comprehensive assessment of the long-term effects of reduced energy consumption" - approx. Transl.).
218 healthy men and women aged 21 to 50 years old were divided into two groups for two years. In the first, it was allowed to eat anything and as much as necessary - in a word, to eat as they used to. In the second, study participants ate 25% less than usual. Members of both groups were examined every six months.
Of course, unlike experiments with rhesus monkeys, a time span of just two years cannot show whether dietary restriction can reduce or slow the onset of age-related diseases. However, Calerie was researching another, equally important one - the early signs of heart disease, cancer and diabetes.
The results published in 2015 were very positive. In the blood of members of the group that ate less, the ratio between "good" and "bad" cholesterol increased in favor of the former, the number of molecules warning about the formation of a tumor (the level of tumor necrosis factor, TNF. - Approx. Transl.) Decreased by 25%, and insulin resistance, a telltale sign of diabetes, dropped by about 40% compared to those in the second control group, where people ate normally. In addition, members of the first group had lower blood pressure.
Admittedly, some of the benefits listed above may have been associated with weight loss, and earlier studies by Calerie support this. “What's very clear is that in the long run, being overweight is bad for your health,” says Roberts.
Diseases previously associated exclusively with age are now found in obese people.
However, the results of recent studies indicate that for those with a lean body (with a BMI of 18.5 to 25), the benefits of reducing the diet are quite significant.
It is clear that further research is needed if we want to state something for sure. And if you decide to try it on yourself - first consult your doctor.
In the meantime, researchers working with primates hope their rhesus monkeys will help understand how dietary restrictions lead to such health outcomes.
For almost 30 years, scientists have been collecting data on the life and death of 200 animals, on the state of their blood and tissues. This work, according to the National Institute on Aging and the University of Wisconsin, will sooner or later shed light on how restricting calorie intake delays aging.
Does reducing the amount of food eaten lead to the fact that the metabolism works more efficiently? Is there a molecular switch in the aging process? Or are there other mechanisms of life and death that we are not even aware of?
Perhaps we will not get answers to these questions soon. And the importance of what happens to primates like Sherman cannot be overstated.
And while scientists don't have a simple explanation yet, restricting calorie intake is perhaps one of the most promising avenues in research on how to improve our health and extend our lives.
“From everything we've seen, nothing indicates that calorie restriction won't work for humans,” Roberts emphasizes.
Unlike treatment with medication, this method does not have a long list of possible side effects and consequences.
“Our members didn't feel hungry, their moods were normal, and their sex life didn't deteriorate. We tried pretty scrupulously to find at least something bad, but we didn't find it,”says Roberts.
Some of the weight loss might be expected to result in a slight decrease in bone density, she says, but as a precaution, the study volunteers took a small calcium supplement.
Despite the promising results, Roberts admits, the Calerie study is only the first of its kind.
“I don’t think any of us can say with complete confidence: ok, we recommend this to anyone,” notes Susan Roberts. “But the prospects are extraordinarily exciting. Nobody wants to live out life with disease. The ability to postpone the time of their emergence and development is what we all want."
Alex Riley
