Diet and Exercise Myth #15: Weight gain is an inevitable part of ageing

If you’re already past your thirties, did you notice your metabolism start to level down at some point?

Many people find it a bit harder to stay trim with each passing year, and that their waistlines don’t seem respond to dieting efforts quite as strongly as they once did.

Is this impression correct? Is the effect real?

It is true that your metabolism naturally slows down as you age, but it’s not by a lot - and it certainly doesn’t mean that weight gain is inevitable.

It’s estimated that your basal metabolic rate peaks somewhere in your late twenties, followed by a slow and gentle decline of about 10% by the time you hit your 50’s. The decline then starts to get a little steeper, reaching about 20% by the time you reach your 70’s.

As you can see, the rate of decline in base metabolic rate is quite small. And it turns out that your age, in and of itself, is not actually a big factor at all.

In fact, the more important drivers of a slowing metabolism are the lifestyle changes that tend to occur as you age. The great news here is that these lifecycle factors are 100% within your control, regardless of your age!

The two biggest drivers of slowing metabolism are:

1. Loss of lean muscle mass. Sarcopenia is the medical term used to describe the loss of skeletal muscle mass and strength as a result of ageing. Muscle mass is the biggest single driver of basal metabolic rate. Left unchecked, the average adult can expect to lose 3-8% of their muscle mass every decade after the age of 30.
   
2. Decreased activity levels. The older we get, the more sedentary we tend to become. Physical activity is one of the most important sources of calorie consumption, and most people simply don’t move as much as each year passes.

So while getting older is inevitable, gaining weight is not. 

All it takes to completely overcome the natural decline in metabolism is to stay active. Which of course is solid advice for anybody at any age. With respect to that activity, you really can’t beat resistance training - it’s not just for the young ones.