The Age - Metabolism Myth

There I was, once again. Somebody found out I was a trainer and the inevitable questions about diet, exercise, and fat loss were being asked. Don’t get me wrong, I absolutely love answering health and fitness questions. There is so much bad science out there. Anything that I can do to point somebody in the right direction or correct them on a misconception is my pleasure. However, the conversation usually goes something like this.

Them: “I eat healthy all the time and can’t seem to lose the weight”

Me: “Well that’s great but quantity is what matters. It doesn’t matter how healthy a food is. If you eat too much, you won’t lose the weight.”

Them: “Well I’ve been staying away from sugar and processed foods. Those are bad for you.”

Me: “That doesn’t really matter. I eat plenty of sugar and processed foods, but I keep track of my calories and I stay very fit and healthy.”

Them (skeptical look): “I used to be able to eat like that. But you won’t be able to keep that up forever. Your metabolism slows down as you get older.”

Doh! This is about the point when I imagine strangling this person like Homer Simpson so often does to Bart.

I’m 29 currently. I’ve been hearing this same line since I was 22. I’m still waiting for that magic age where all hell breaks loose and I take my rightful place as an overweight American adult, a slave to the mysterious metabolic woes that we all warn our younger, skinnier friends is coming for them. The horror!

But of course, I’m being too harsh. This is a common misconception, and a dangerous one!

What The Hell Is A Metabolism?

Most people recognize the word, but what does it mean???

Metabolism is a term used to describe all the combined processes that work to keep the human body alive.

Great! Now we are all more confused! While this may be the technical definition, let’s break this down a bit. A person’s metabolism is the amount of energy that is used daily to keep the body functioning properly. This is usually referred to as basal metabolism. If we do not eat enough food to provide our body with the energy needed to function, we die of starvation. In addition to providing enough food for our body to stay alive, we also need to account for any energy that is used up during movement. This includes any daily activity such as work and exercise.

So, for our purposes, let’s refer to our overall daily energy requirement as metabolic need. Generally, we use Calories to describe this amount of energy. So, if we say the average person should consume 2000 Calories per day to maintain their weight, their metabolic need is 2000 Calories. This is where body fat comes in. If my metabolic need requires 2000 Calories per day and I only eat 1500, I will use my fat stores to replace the shortage. We call this fat loss! If my metabolic need requires 2000 Calories per day and I eat 2500, my body will store the excess. Boom. That’s how we all gain weight.

In Short:

Daily Metabolic Need = Energy needed to keep the body functioning + Additional Energy used for movement (daily activities and exercise)

Energy Consumed > Daily Metabolic Need = Fat Gain

Energy Consumed < Daily Metabolic Need = Fat Loss

Energy Consumed = Daily Metabolic Need = No Change

So, Metabolic Need Doesn’t Decrease With Age?

Ok, to be fair, metabolic need does decrease with age…a little bit. According to studies, metabolic need will decrease by 3-5% per decade due to age. If the average person has a 2000 Calorie metabolic need at age 25, they would have a metabolic need of 1900-1940 Calories at age 35. This means that in order to counteract this, skip the morning banana or drink one less beer… Aging isn’t exactly the metabolic landslide that we thought it was. So the question remains:

If age isn’t the reason for metabolic need decrease over time, then why the hell is it so hard to lose fat as you age???

These same studies have found that fat-free mass accounts for 70-80% of variance in the metabolic needs of different people. Fat-free mass is the collective total mass of your skeleton, organs, muscle mass, and other tissue. Basically everything except fat. Now of course, you cannot change your bones, organs, or most other tissues in the body. Muscle mass, however, can be changed. And here we come to the root of the problem and the actual reason why it’s harder to lose fat as we age.

As the typical American ages, they:

1) Eat More Calories (increased daily energy consumption)

2) Exercise Less (decreased daily metabolic need from movement)

3) Lose Muscle Mass (decreased daily metabolic need for bodily functions)

In summary, age isn’t the major reason behind our weight loss struggles. The biggest contributor is a loss of muscle mass due to less exercise. Add in larger portion sizes and a few more beers and Viola! You’ve gained 50 pounds over the last 10 years!

So, while it’s fun to blame our age for our health problems, try to remember that you are not destined to a life of weight loss struggle. Cut down on the portion sizes and learn to lift some weights a couple times a week. The longer you avoid the gym, the more muscle mass you lose and the less you can eat. It’s that simple. Age is just a number, and for some people, an excuse. Now that you’ve got all the facts, get your butt to the gym, do some squats, and as always…


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