Over the last few years, many studies have shown the benefit of calorie restriction and intermittent fasting. Benefits include weight loss, increased fat burning, muscle gain, improved energy levels, and improved insulin sensitivity.
A recent trial, known as CALERIE (Comprehensive Assessment of the Long Term Effects of Reducing Intake of Energy) tested the metabolic effects of calorie restriction in a group of 53 healthy, non-obese volunteers who cut calories by 15% over two years.
It found that calorie restriction decreases oxidative stress, a process that has been linked with aging and age-related conditions such as Alzheimer’s and Parkinson’s, cancer, diabetes, and others.
One of the mechanisms for this improvement is that restricting calories can slow your basal metabolism. While we often think that, in terms of weight loss, a slower metabolism is as “a bad thing”, by-products of metabolism do accelerate aging processes. The study found evidence that calorie restriction enhances resting energy efficiency, resulting in less oxidative damage to tissues and organs.
Another new study, however, found that intermittent fasting diets were better than daily calorie restriction at clearing fat from the blood and thereby reducing the risk of cardiovascular disease.
Researchers at the University of Surrey assigned overweight participants into either the 5:2 diet or daily calorie restriction diet. Those on the 5:2 diet ate normally for 5 days and then fasted for 2 days on 600 meal replacements, while those on the daily diet were advised to eat 600 calories per day fewer per day than their estimated requirements for weight maintenance.
The study found that those on the 5:2 diet cleared post-meal fat more efficiently than those undertaking the daily diet, and also experienced a reduction in systolic blood pressure which further reduces the risk of cardiovascular disease.
Dr Rona Antoni of the University of Surrey does acknowledge however that the 5:2 diet is not for everyone. “As seen in this study, some of our participants struggled to tolerate the 5:2 diet, which suggests that this approach is not suited to everybody; ultimately the key to dieting is finding an approach you can sustain long term”.
Another approach to fasting and calorie restriction might be to limit the number of hours in which you eat. Studies with mice have found that those who had access to food at restricted times lost weight and improve a number of health markers, as opposed to mice given unrestricted access to the same amount of food. Time-restricted feeding has been shown to treat and prevent conditions such as obesity, diabetes, fatty liver, high cholesterol, and metabolic disorders.
There are different ways of achieving time-restricted eating but 16:8 is very popular. This is where you eat all of your food during an 8-hour window and fast for 16 hours overnight. The idea is not to cram 3 meals into that 8 hour period but to eat only 2 nutritious meals.
Again, this approach does not work for everyone, and as always with nutrition and diet, it’s a case of finding out what suits you as an individual and fits in with your lifestyle.
The evidence is clear, fasting and reducing the amount we consume benefits not only our weight but all of our markers of health, while at the same time restoring our energy, vitality, and motivation. If incorporating into your life any of the above approaches seems way too daunting, why not try a detox week at Homefield, where everything is done for you? You will be served delicious fresh juices and soups, take part in some great exercise classes, indulge in some fabulous treatments, and learn how to make healthier choices.