Most people would agree that exercise is generally a good thing but whether it actually helps weight loss is much less clear. Once reason is that exercising makes people feel hungrier and this in turn can make them eat more. However, new research discussed by Dr Briffa suggests one form of exercise – HIIT – might have the opposite effect and actually suppress the appetite. This is from Dr Briffa…
The heightened hunger that can come as a result of exercise does not happen to everyone, but my experience tells me it tends to be more common in individuals who engage in relatively prolonged exercise such as extended running or cycling. In my book Escape the Diet Trap I made the observation that ‘high intensity intermittent exercise’ (short, intense bursts of activity interspersed with longer periods of rest) tended not to make people hungrier.
Now, recently, a study was published which lends at least some support to these observations.
In this research, overweight, sedentary men were (at different times) subjected each of the following conditions:
1. continuous exercise at 60 per cent of maximum oxygen utilisation (VO2 max) for 30 minutes
2. 1 minute at 100 per cent VO2 max alternating with 4 minutes of 50 per cent VO2 max, repeated for a total exercise time of 30 minutes
3. 15 seconds of exercise at 170 per cent VO2 max alternating with 60 seconds at 32 per cent VO2 max for a total of 30 minutes
4. Rest (no exercise) for 30 minutes
After each condition, the men were fed a meal with a set number of calories. 70 minutes later, they were given access to food that they could eat freely. Food intake and activity levels were monitored on the day of each experiment and the following day (a total of 38 hours).
Interestingly, the intakes of the test meal 70 minutes after conditions 2 and 3 were lower than that when no exercise was taken (condition 4).
Also, energy intake over 38 was lower after condition 3 than after conditions 1 and 4.
Interestingly, I think, after condition 4, levels of the appetite-stimulating hormone ghrelin were lower, and blood sugar levels higher, than after the other conditions. Levels of lactate were also higher, and there is some evidence that lactate suppresses appetite .
This study was short, in that each condition was only tested once. However, there is at least some evidence here to support the idea that high-intensity exercise not only may not stimulate the appetite, but might even suppress it.
More (including references for the research) at: Evidence suggests one form of exercise might actually suppress appetite