As fitness buzzwords go “metabolism” is a good one. There’s a lot of real estate in the health and fitness space dedicated to ever new and unique ways to speed up the resting metabolism, and it’s easy to understand why. Imagine a scenario where you could consume a great degree more but not gain weight. This process would be like receiving a passive income, invest some hard work and time initially and then sit back and reap the rewards. There’s also a widely held idea that metabolism slows drastically as we age, with many believing that at some point during our mid 30s or 40s metabolism takes a nosedive, explaining the “middle age spread” that can occur around this age. The truth however, according to current research, actually consists of a mix of bad news (in relation to metabolism being something we have a great degree of control over) and good news (in relation to metabolism dropping off the edge of a cliff in our 30s).

To cut to the chase early, the majority of methods that promise to boost metabolic rate will fall into two distinct categories: dangerous or useless.

Put simply, metabolism is our basal metabolic rate or BMR, and refers to the housekeeping duties the cells in our body perform and the energy, in the form of calories, this requires. Cells forming muscle, nerves or internal organs require more energy therefore, one legitimate way in which the metabolic needle can be moved is through the addition of muscle mass. More muscle means more metabolically demanding muscle cells, which translates into a higher resting metabolism, in fact, individual differences in body composition appear to underlie most of the variation in metabolism from person to person. Unfortunately though, this isn’t the holy grail of metabolism boosting many are seeking. Not only is adding significant amounts of muscle mass a difficult and arduous process for the average person, it also appears that increases in muscle mass will often only lead to a very small increase in basal metabolic rate.

Body weight and metabolism have a somewhat complex relationship but simply put, the larger the person, the more cells their body will comprise of, more cells equal a greater use of energy to maintain. This among other complex internal mechanisms, goes a long way in explaining why weight loss often plateaus despite conditions remaining the same. As the body becomes smaller, so do its energy requirements.

Now for some positive news. Recent studies have found that contrary to popular belief, metabolism remains at a constant between the ages of 1 to 60 years of age. Even more surprisingly, life events such as puberty, pregnancy and menopause appear to have very little impact. This tallies with the seemingly impossible task that is shifting the metabolism in any meaningful or long-lasting way and that may even pertain to damaging or “breaking” it also. Often associated with crash diets or sedentary living, what’s more likely to occur in these scenarios is malnutrition and a decline in physical health with the former likely to cause a behavioural swing to overeating in order to combat hunger/starvation, which then causes weight gain and ultimately leads to the assumption that the metabolic “fire” has died down.



In truth, there may be some comfort to be had in knowing how little is under our control when it comes to shifting the metabolic needle. There are many components that make up the calories out portion of the energy equation, some we can control (exercise/activity) many we can’t (N.E.A.T, metabolic rate etc) but the side that appears to require the most external effort appears to be the input side of this equation, reinforcing the need to place our focus on the what, and sometimes more importantly, the how much of what we consume.