“Give your body a break from food, but not to the point of starvation.”
According to the researcher, a good health can be achieved by reducing the amount of meal portions.
James R. Mitchell, American researcher and associate professor of Genetics and Complex Diseases at Harvard T. H. Chan School of Public Health, runs a lab with the primary goal of understanding how nutrition affects longevity and health. His key research includes unraveling mechanisms of stress resistance by short-term dietary restriction, expounding on the effects of diet on susceptibility to infectious disease and comprehending the impact of DNA damage on metabolism and ageing-related disease.
“In the original observation, conducted by researchers on rats, they deprived rodents of 50% of what they would normally eat, starting from very early in their life, and they lived 50% longer.”
During his recent trip to Thailand, Mitchell said his primary focus is in dietary restriction, which, through his studies, extends lifespan in various types of organisms but also attests to improved metabolic fitness and stress resistance. For example, “The ageing process is an intriguing field of study,” said Mitchell, 45. “One of the oldest tools in understanding how ageing works is what is called dietary restrictions, or calorie restrictions . In the original observation, conducted by researchers on rats, they deprived rodents of 50% of what they would normally eat, starting from very early in their life, and they lived 50% longer. That basic observation has been repeated over the decades in many different organisms. “We still don’t know how it works, but in the meantime, we have extended our research into other organisms, such as flies, spiders, worms, yeast and even primates, and found that from yeast to rodents, the benefits of dietary restriction include extended longevity, an improved health span and increased resistance to stress.”
Mitchell’s is mainly interested in how dietary restrictions make humans more resistant to various forms of stress. “We are thinking about particular stressors, and the one we model on the lab is the stress of surgery, especially when you know it is coming.” He said studies had unearthed that short-term application of diverse dietary restriction regimens, lasting from three to seven days, provide significant protection in rat models of surgical stress, including injury to kidney, liver and brain. Their long-term aim is to translate these benefits to the clinic, beginning with the area of preoperative nutrition, he said.
When asked about the safe estimate on dietary restrictions, Mitchell said that in a typical experiment, what they would do is reduce food intake by 30%. Just to get an idea of a healthy range, he noted that in the original experiment they were able to reduce it to between 50-60%. Beyond that, it is very unhealthy, he said, the aim is to not reach starvation point. It is all about cutting food intake by half of a healthy rodent, which in turn would extend its life span and protect it from things like surgery. What he is trying to find out is whether people really have to reduce food intake and what it is they have to take out of the diet to cause favourable results.
“What we found is that it is not just the total calorie content but the protein that has to be taken into account,” explained the researcher. “So if you reduce the protein in the diet, than your body responds as if calories are being reduced. Protein is composed of amino acids. One has to also take into consideration that it can come from different sources, such as animals, plants, pasta and grains; everything has protein just different amounts.
“Each has a different amino acid content, so we are still trying to understand just how much protein, and which protein you eat controls health benefits we are looking into. So our aim is to elucidate the specific role of protein and essential amino acid restriction in the benefits of dietary restriction.”
“So if you reduce the protein in the diet, than your body responds as if calories are being reduced. Protein is composed of amino acids.”
On the topic of nutrition, Mitchell said more could be done to educate the public on what is health. He said obesity was at its all time high in most countries. In the US, he said, the United States Department of Agriculture (USDA), goes back and forth about the proper diet to follow. “Yesterday fats were bad so what they did was replace the fat with sugar, then later they recommended limiting sugar in your diet, so the public don’t get a clear message.”
Further research is required to figure out why one diet works under one condition and another works under another set of conditions, or maybe, it’s specific to certain people. He suggests the best way to approach nutrition is to have common sense. Fresh ingredients and chemicals free products are what comes to mind. Overeating is an another issue that should be addressed. With regards to gorging, Mitchell said: “Your body has mechanisms to shut down appetite and the recommendation is to eat slower. Talk, eat with the family, so you eat at a slower pace. In the US, we are taught three square meals a day with a big breakfast in the morning. There is no good evidence to support this theory and we found that in fact this is not the case.
“We have to re-examine how we look at our eating habits and nutrition. I don’t think being hungry is necessarily a bad thing, especially for healthy adults, I don’t advocate it for developing children or anyone who suffers from malnutrition. Give your body a break from food, but not to the point of starvation.”
Information adapted from the Bangkok Post