What is the best way to lose weight? This question is particularly relevant when we tend to abandon good dietary habits on holiday and overindulge.
Much has been written about the effectiveness of the so-called 5:2 diet, which was popularised by a BBC television programme and involves restricting calories by 75 per cent on two non-consecutive days and then eating normally for the rest of the week.
Another way of implementing this kind of diet, which is known as intermittent fasting, or IF, is to cut back to 500 calories or eliminate food entirely on alternate days.
Intermittent dieting has been well studied and offers all the benefits of eating less, while reducing the problem of sticking with a reduced-calorie intake on a daily basis. After all, you get to eat normally most days. But there is a way to boost the health benefits of this kind of diet and supercharge your weight loss by adding cardio exercise to the mix.
A team of researchers at the University of Illinois divided obese volunteers into four groups: one group practised alternate-day fasting; a second group practised endurance exercise three days a week; a third group did both IF and exercise for 12 weeks; and the fourth control group did none.
The results were pretty striking: the combined exercise and IF group lost an average of 6kg, compared with 3kg weight loss for the IF-only group and just 1kg for the exercise group.
Interestingly, not only did the diet-and-exercise combination produce more weight loss, but it also helped the subjects’ blood lipid profiles, which are an indicator of heart attack risk. In the group that did both endurance exercise and restricted calories, so-called “bad” LDL cholesterol decreased 12 per cent from the baseline, while the “good” HDL cholesterol increased by an impressive 18 per cent. The other interventions produced no HDL benefit.
What is interesting about this and similar studies is that there has been a growing consensus that diet is much more important than exercise in maintaining good weight. But it is now clear that the two in combination are much more effective than either approach alone.
In addition, the endurance training in this study, which was performed on exercise bikes and elliptical machines in a gym, lasted 25 minutes and was at just 60 per cent of maximum heart rate, growing incrementally to 75 per cent of the maximum at the end of the study.
Surabhi Bhutani, the postdoctoral researcher who led the study, says this is because the subjects were obese and the researchers wanted to avoid the risk of cardiac problems.
But there is quite a lot of evidence that high-intensity interval training, or HIIT, involving short bursts of exercise at close to the maximum heart rate, followed by recovery periods, or slightly longer bursts of cardio exercise at 90 per cent of maximum heart rate, is more effective than slow endurance training. And it has the added benefit of taking less time.