The recommended intake of calories varies depending on age, metabolism and levels of physical activity, among other things. Generally, however, the recommended daily calorie intake is 2,000 calories a day for women and 2,500 for men, according to the NHS.
“A calorie-restricted diet provides all the nutrients necessary for a healthy life but minimises the energy (calories) supplied in the diet”, said one of the study’s authors.
The study’s main discoveries found that a calorie-restricted diet increases the lifespan of mice and delays the onset of age-related chronic diseases such as cancers, heart disease, and stroke in rodents.
There are also hints that people who eat a calorie-restricted diet might live longer than those who overeat. In addition, calorie-restricted diets beneficially affect several factors of ageing, including decreased insulin sensitivity, which can cause diabetes.
However, a major factor in the age-related decline of bodily functions is the accumulation of “oxidative damage” – an imbalance of antioxidants – in the body’s proteins, fats, and DNA which could rapidly increase ageing.
Researchers enrolled 36 healthy overweight but non-obese young people into their study. A third of them received 100 percent of their energy requirements in their diet; the caloric restriction group had their calorie intake reduced by 25 percent; and the control group increased calorie intake by 12.5 percent.
The researchers found that a 25 percent caloric deficit for six months, achieved by diet alone or by exercise, decreased 24 hour calories burned.
The study’s analysis of genes involved in cell formation indicated that a reduction in calories increased the number of mitochondria in muscles. Calorie reduction also reduced the amount of DNA damage in the participants’ muscles, paving the way for longevity.
Clinical physiologist Leanne Redman, who headed the study at Pennington Biomedical Research Center in Baton Rouge, said the first challenge was finding people willing to take part. After all, they would have to cut their typical plate for all three meals by 25 percent.
“I don’t know if you understand the rigour of what it means to do calorie restriction every day,” she says, but the volunteers stayed committed.
Unsurprisingly, the people cutting calories lost a fair amount of weight – on average, 25 pounds. Those in the control group gained as much as 4 pounds.
However, whilst the study’s findings showed positive signs that a calorie-restricted diet does increase longevity, cutting calories is not without its limitations.
Biochemist Valter Longo, who studies longevity at the University of Southern California, said severely restricting calories for a time can mean you’re more likely to gain weight in the end.
“Basically, you have to eat progressively less to maintain the same weight,” explained the PhD researcher.
Longo was also concerned about the potential for muscle loss and a weakened immune system in those on severe calorie-restricted diets.
Instead of chronic calorie restriction, Longo explained that “mini-fasts” could be the answer to longevity. These are short reductions in calories to just 900 a day for five days a month, which he said have the benefits of fasting without the potentially negative long-term effects.
Whilst it may not ultimately lengthen your life, Longo said, it can certainly help you maintain a healthy weight and avoid the kinds of chronic illnesses that can shorten it.
It comes after day-time television show, This Morning, attracted criticism after nutritionist Gabriela Peacock advocated eating 500 calories in a day as part of an intermittent fasting regime on the programme.
She advised that “the most effective one is where you fast for three consecutive days and you do 500 calories for women and 600 calories for men”.
The comments come after This Morning received nearly 2,000 Ofcom complaints for airing a segment that promoted an 800-calorie daily diet as part of a “rapid weight loss” programme.
These studies stress that anyone, especially those with a history of eating disorders, should talk to their GP before rapidly cutting their calorie intake.
Post source Daily Express