Rapid weight loss without losing muscle: combine intermittent fasting and cardio
Sports scientists at the University of Illinois at Chicago may have stumbled on a perfect way for overweight people to lose weight. Their study suggests that a combination of intermittent fasting and cardio training results in considerable weight loss while maintaining lean body mass.
The publication of the scientists' study, a few months ago in Obesity, is a triumph for the intermittent fasting movement. They argue that the human body is capable of functioning perfectly well for hours without taking in food. When this happens it starts burning body fat, and holding on to muscle tissue.
Respected scientists and traditional trainers advise athletes who want to lose weight to concentrate on eating small quantities of food during the day. This is believed to keep the body's energy burning topped up and to prevent the breakdown of muscle mass. This is exactly the opposite advice from what the supporters of intermittent fasting recommend.
Surabhi Bhutani's publication in Obesity backs up the intermittent fasters. Bhutani did an experiment with 64 obese but healthy people, with an average BMI of 35. Her experiment lasted 12 weeks.
Bhutani divided her subjects into four groups of 16 test subjects in each.
The first group did nothing at all during the experiment and functioned as the control group.
The second group did a kind of intermittent fasting, eating only a quarter of the amount of calories they normally would on alternate days [Alternate day fasting]. On those days the subjects consumed one meal – of 450 kcal – that consisted of 22-26 percent protein in energy terms.
The third group did cardio training on stationary bikes and cross trainers three times a week [Exercise]. At the start of the study the subjects exercised for 25 minutes at 60 percent of their maximal heart rate; by week 12 they'd increased that to 40 minutes at 75 percent of their maximal heart rate.
The fourth group did both exercise and intermittent fasting [Combination]. The subjects trained on the days that they ate just one meal.
The figures below show that the combined approach worked unexpectedly well. The subjects in the combination group lost twice as much weight than the subjects who only fasted, but they lost hardly any lean body mass.
What's more, the combination of intermittent fasting and cardio improved the subjects' cholesterol levels more than the other approaches.
"The combination of alternate day fasting plus exercise may be implemented as a viable lifestyle intervention to help obese individuals lose weight, retain lean mass, and lower their risk of coronary heart disease", the researchers conclude.
Obesity (Silver Spring). 2013 Jul;21(7):1370-9.
Animal study: slimmer and healthier with part-time fasting 30.12.2013
Confining the time in which you eat makes you slimmer 12.07.2012
Lose weight faster by eating carbs in the evening only 24.08.2011