High-intensity interval training (HIIT) proved to be more effective in preserving muscle mass during a diet. As a result, it limits the decrease in your energy expenditure and reduces the chance of ‘yo-yo dieting’. In mice, at least, according to researchers from the University of Alabama, Birmingham
“HIIT against yo-yo dieting”
Here we go again. The well-known yo-yo effect. The reason to start discussing this again is the recent study from Alabama [1].
The researchers started with a known fact. If you lose weight through a calorie deficit, the weight loss is lower than you would expect based on the deficit itself. This is because during weight loss, the resting energy expenditure decreases. So, you’re taking in less, but also burning less. In practice, this means that when you start eating more again, it leads to a quicker increase in weight. This is evident, among other things, from the fact that 80 percent of people who lose weight regain it within 4 to 5 years.
A major cause of the decreased energy expenditure is the loss of muscle mass. The researchers therefore wondered if this decrease in energy expenditure could be limited. A commonly used way to create a calorie deficit is, of course, the combination of eating less and moving more. Whole books could be written about its implementation. The Alabama researchers looked into the form of additional movement. They compared the effect of a diet in combination with moderate-intensity training (‘traditional cardio’) to that of high-intensity interval training, or HIIT. This involves short periods of maximum effort alternated with periods of active recovery at moderate intensity lasting two to four minutes. This is then repeated several times, for example, four to five times.
In the study, three groups of mice were used that had been given a high-fat diet for 11 weeks. This was followed by 15 weeks of one of the following protocols:
- 25% energy deficit. 12.5% through calorie reduction, 12% through increased expenditure by moderate-intensity training.
- 25% energy deficit. 12.5% through calorie reduction, 12% through increased expenditure by HIIT.
- Same high-fat diet (control group)
Both groups on the weight-loss regimen showed improvements in glucose and insulin sensitivity. However, HIIT had a greater effect on muscle glucose uptake. Only in the HIIT group was the loss of muscle mass and the reduction of resting energy expenditure limited. The effect of glucose uptake would, apart from the reduced chance of regaining lost weight, decrease the chance of diabetes.
Cardio or HIIT? The practice
One of the advantages of HIIT, according to the researchers, is that it takes less time for the same result. They refer, among other things, to research showing that people who do 60 minutes of cardio at moderate intensity burn more calories, but lose less weight than when they do 20 minutes of HIIT. Because lack of time is often cited as a reason for insufficient exercise, HIIT could be a practical solution.
Time-wise, there’s no arguing with that. However, in practice, I think there is an important difference in the experience and possible implementation of both. HIIT, because of the moments of maximum effort, even though these are short, is really a workout. Traditional training, however, can be achieved through everyday movement such as cycling or walking. Although you need less time for HIIT, you have to make time for it. We have recently devoted articles to research on practical ways to make movement a part of your routine. “Anything that raises your heart rate,” was the advice. With HIIT, that’s more difficult. At least, your heart rate rises faster and higher, but that’s not always practical in everyday life.
Suppose you indeed live the right distance from work to replace the car with a bicycle. As I write this, I look outside, and it’s pouring rain. I can think of enough reasons why you wouldn’t want to sprint full out every 2
