Muscle research helps obese dieters take the strain

Obesity isn't just bad for your health; it's also hard work, putting a substantial strain on leg joints, tendons and muscles. Losing weight is clearly the answer - but what if that means losing muscle as well as body fat?

New research at the University of Hull is looking at where obese people lose most weight and whether this does actually reduce the stress on their muscular system or not. The long-term aim is to determine what kind of exercise and how much of it would be the most beneficial as part of a weight loss programme.

"Obese people tend to develop strong leg muscles, but relative to their weight, their muscles are still weaker than those of the average person," says lead researcher Dr Tom O'Brien, of the University's Department of Sport, Health and Exercise Science.

"Exercise is already difficult for people who are clinically overweight but if there is muscle loss during dieting, then movement may still be demanding for the obese patient."

Previous research indicates that obese people cope with their additional weight by developing distinct ways of moving, so the researchers want to test this theory and look at any changes that occur as people lose weight.

The research, a collaboration with the University's Humber Obesity, Nutrition, Education and Innovation (HONEI) project, will assess 20 volunteers at the start of a diet-induced weight loss programme, and then again after three months.

Each volunteer will have their walking movement analysed to assess how they use their joints and what forces are applied during walking. The researchers will take individual measurements at the ankle, knee and hip joints, to determine the strength of the leg muscles, while ultrasound imaging will provide information on muscle size and structure.

"Our bodies require a lot more energy to retain muscle than fat," explains Dr O'Brien. "So as people reduce their calorific intake, the body will sacrifice muscle as well as fat stores - unless appropriate exercise is taken.

"Although by losing weight, people should be putting less demand on their muscles, if muscle is lost at a similar rate to body fat, there could overall be no change in stress on muscles.

"To lose weight, you need to burn more calories. But there are various ways to do this and some may be more appropriate for obese people than others."

The researchers hope the data from this pilot study will lead on to a larger research project, comparing the benefits of strengthening exercises with cardiovascular activity for weight loss in obese people.

Source: Hull University