Have you noticed your waistline is increasing as you get older? Perhaps weight loss doesn’t come as easily now as it did when you were younger.

The truth is, even if you adopt a healthy diet and engage in regular physical activity it’s much harder to prevent weight gain as we age. Now, a new study out of Sweden may have discovered the reasons for the increase in body weight.

Published in the journal Nature Medicine, the researchers suggest “lipid turnover rate” decreases with ageing. This is the rate at which lipid or fatty acids in fat cells is removed and store.

The reduction of “lipid turnover” makes it easier to gain body fat, even if we’re eating the same amount of calories and our doing the same amount of exercise.

Previous studies have found an excess in body fat is linked with a decrease in the removal of fatty acids. But is the rate constant over a life span or does it change during weight gain or weight loss?

Over an average period of 13 years, fat cells were analysed in 54 male and female participants. Regardless of whether the participants experienced weight loss or gained a few extra kilos during the study period, there was a decrease in the lipid turnover rate in their fat tissue.

According to the study, those participants who didn’t compensate for this change by eating fewer calories gained an average of 20% more weight.

Weight-loss surgery may help increase lipid turnover

Interestingly, the study also analysed lipid turnover in 41 women who had undergone weight loss bariatric surgery to ascertain how the rate affected their ability to keep the weight off long term.

The new research found only in the women who had a low lipid turnover rate pre-surgery were able to increase their lipid turnover after their weight-loss surgery and maintain their reduced body weight.

Substantial weight loss doesn’t appear to be driven by changes in the fatty acid removal, but instead by the rate of lipid uptake in the fat tissue.

Professor at Karolinska Institutet in Sweden and one of the study’s main authors, Peter Arner, said this new research could give a greater understanding in why people gain weight and new ways to treat the obesity crisis.

“The results indicate for the first time that processes in our fat tissue regulate changes in body weight during ageing in a way that is independent of other factors”, he said.

How do you increase the lipid turnover rate?

Thankfully, it’s not all doom and gloom and there are ways to speed up your lipid turnover.

Previous studies looking into lipid turnover in relation to weight gain has found one way to increase the rate in the fat tissue is to exercise more.

“Understanding lipid dynamics and what regulates the size of the fat mass in humans has never been more relevant”, said co-author and senior researcher at Karolinska Institutet, Kirsty Spalding.

“Obesity and obesity-related diseases have become a global problem”, she added.

According to an earlier study published in the Journal of Internal Medicine, people who engage in regular physical activity tend to be of good metabolic health and have high metabolic flexibility.

In obese patients, exercise has the beneficial effect of reducing intramuscular lipids which could be linked to the improved lipid turnover.

These findings show the speed of lipid turnover is an important factor in the long-term changes in body weight and long-term results of weight-loss surgery.

Simply put, if you want to prevent weight gain as you age, it’s time to get moving.