A study published this month in Science has drawn a lot of press attention for it’s surprising finding that our metabolism is largely stable from our 20s to our 60s, only then starting to decline.
Previously people had assumed that the gradual (or for some, not so gradual) midlife spread was largely due to a slowing metabolic rate (the rate at which we burn energy).
Of course, even before we get into the details and limitations of the study, blaming midlife weight gain on a slowing metabolism alone is over-simplifying.
So, back the headline that our metabolism isn’t slowing through our middle age…
Well, yes and no. The study has two limitations.
The first is that it measured each individual at a single point in time and then extrapolated the results. To be more meaningful, each individual would need to have their metabolic rate measured over 4 decades to track any changes.
The second limitation is that the study was looking at fat-free mass only (again at a single point in time), so the results were looking at the metabolic rate per pound of fat-free mass – which means it took no account of the effect of declining muscle mass.
What it does tell us is that our tissues seem to keep a steady metabolic rate between the ages of 20 and 60, but of course, the more muscle you have, the higher your overall metabolic rate, and the lower your muscle, the lower your metabolic rate.
At midlife due to the hormonal changes both men and women experience, we’re naturally losing muscle mass (and strength) from our early 30s onwards, and of course, that means that our metabolism is slowing.
What’s this mean in practice? Well if you were carrying say 30kg of lean muscle on your frame in your 20s, and by your late 40s that was down to 20kg of lean muscle, you’ve lost 10kg of muscle.
The metabolic rate of muscle is around 10 to 15 calories per kilo per day (more if you’re exercising a lot) so you could be burning between 100 and 150 calories a day less as a result of the muscle loss.
If you’re eating habits stay the same (and many of us not only eat more, but eat more of the wrong kind of things at midlife), then of course, your body fat, and your midlife spare tire will increase.
What does this mean if we want to avoid the middle age spread?
Well, first up, don’t blame it on your metabolism and accept it as inevitable. There are many factors at work and you can work with your hormones and body to offset the negative effects, which is exactly what we coach our clients to do and why they get such great results. Move more, make sure you’re getting up from your chair regularly and moving around – many of us have moved less since lockdown and the advent of home working. What we call NEAT (non exercise thermogenesis) will help you burn more calories.
As we’re losing muscle mass at middle age we want to work to preserve or increase it – not just so we can boost our metabolism, but so we maintain our strength and have a better quality of life.
The more muscle you have, the higher your metabolic rate. You don’t need the gym, you can use your bodyweight or simple equipment like resistance bands and kettlebells at home, and our clients consistently get great results by training in this way.
Aim to train each body part twice a week, with time off for recovery in between.
Because time is a valuable commodity for many people, we prefer to utilise short high intensity interval training sessions of 15 to 20 minutes first thing in the morning. We recommend doing it fasted as your energy stores (glucose and glycogen) are low, your body will turn to fat for energy. A study by Bath University found fasted training burned twice as many calories as fed respondents.
Be aware though, you really only want to do this for short sessions as you don’t want to spike your stress hormone cortisol too high, and we recommend HIIT or cardio fasted, and resistance training fuelled.
Aim to cut ultra processed food from your diet, minimise sugars (including hidden ones which are in many foods these days), and front load your carbohydrates early in the day. Breakfast like a king, lunch like a prince, dinner like a pauper.
Shedding your midlife spare tire is not only possible, but once achieved, easy to keep off while still enjoying the finer things in life.
Once you understand what’s going on with the body and mind, and learn to work with it, making these lifestyle changes not only becomes easier, but sets you up for long term success, physically and mentally.
We’re proud of the success we get for our clients not only over and over with each new client, but the continuing success stories for years as we help them bed in positive lifestyle changes.
It’s because we love what we do, delve into the science, road test it, adapt it for real life, and come up with easy to implement strategies that get results. Time and time again.
If you’d like to know more, drop Claire or myself a message and let’s have a chat.
