Age vs Metabolism: Strategies to Keep Your Fire Burning

I was with 3 of my closest friends last weekend having some dinner and a couple of drinks when, as usual, we got onto the subject of health and fitness. A normal topic each weekend considering the boys have desk jobs and I am the fitness man of the group. We broached the topic of increasing weight and a couple of reasons why they may be seeing an increase in inches around the waist. What caught my attention was the general consensus that the main reason for the tighter clothes was a ‘slowing down’ of the metabolism. My friends raised the idea that they had the same activity levels and calorie intake they had when they were in their 20’s (they’re now in their mid 30’s) so it must be a slowing metabolism that is the culprit.

 

What is meant by Metabolism?

I asked the boys what each of them understood metabolism to mean, the responses were well thought out but all slightly different. If you were to stop reading for a moment right now and ask yourself what your definition of metabolism would be what would you say?

The most important metabolism definition would be that it is ‘the sum of reactions needed to support the life of an organism‘.

Simply put; Metabolism is the chemical reactions in the body’s cells to change food into energy and maintain life

The components of Metabolism can be broken down into 3 areas;

Component	Description
BMR (Basal Metabolic Rate)	This is the amount of energy (calories) needed by the body to sustain life at complete rest Approximately 70-80%
THERMOGENESIS	This is the amount of energy required to break down food and process nutrients Approximately 5-10%
ACTIVITY	This is the amount of energy burned during movement Approximately 20%

BMR is the amount of energy the body needs to maintain normal function. This includes the energy needed to breathe, circulate blood via a steady heartbeat, grow and repair cells, and maintain healthy hormone levels.

Thermogenesis is the thermic effect of food. It includes the total amount of energy used to:

• Eat (chewing and swallowing)
• Digest (mechanically and chemically breaking down food as it moves along the gastrointestinal tract)
• Absorb, transport, and store nutrients

Activity – The amount of energy expended as a result of physical activity is the only component of metabolism that is entirely within an individual’s control. This includes NEAT (non planned exercise) and EAT (planned exercise). Physical scientists recommend that a person receives at least 30 minutes of moderate exercise per day. Moderate exercise is defined as an intensity level that allows an individual to talk but not sing while exercising.

If we take into consideration; age, weight, height and activity level we can determine our approximate BMR calorie consumption which can provide a solid base point of energy we are expending each day (our metabolism).

 

 Our slowing metabolism

We have all heard the expression ‘you can’t eat like you’re 20 anymore’. This is due to a natural slowing down process of our metabolism through aging. During our younger years 0-30 our metabolic processes tend to be very fast (for most people) due to our bodies growing and developing, which means we can eat a lot and not need to worry as much, due to energy demands. However, once we meet our ‘peak’ ‘prime’ or ‘maturity’ our bodies demands for energy and hormones begins to decline. This results in reduced metabolic processes; particularly in our BMR, due to a decrease in testosterone and estrogen, which, negatively affects muscle mass levels and development.

As we age and our metabolic demands slow down we need to be cognizant of this change and adjust our energy consumption or output accordingly, hence the expression; ‘you can’t eat like you’re 20 anymore’. During our younger years we tend to move much more than we do as we get older. As we age we start to move less and burn less energy resulting in weight gain. We can prevent this if we take in less calories through food but most people don’t.

 

What causes a slow down in metabolism?

ACTIVITY LEVELS

The number 1 culprit and component we generally have control over is our activity levels. As stated above movement tends to reduce with aging and results in a loss of muscle mass and reduced energy expenditure. Research shows that older adults burn roughly 29% fewer calories through NEAT. NEAT is activity outside of planned exercise; i.e. Standing up, cleaning the house, walking the dogs, playing with the kids, grocery shopping, taking the stairs, walking to the store. As we age we tend to take the easy options, which drops our NEAT levels.

MUSCLE MASS LOSS

The average adult loses 3–8% of muscle during each decade after 30. In fact, research shows that once you reach 80, you have roughly 30% less muscle than when you were 20. Because muscle mass is affected by your activity level, being less active is one reason why you lose more muscle with age. A lack of resistance training will exacerbate this process.

Other reasons include consuming fewer calories and protein, as well as a decrease in the production of hormones, such as estrogen, testosterone and growth hormone. Maintaining muscle mass will increase your BMR and result in more calories burned (higher metabolism) at rest.

 

 How can we reduce the effects of our slowing metabolism?

1 – RESISTANCE TRAINING

Resistance training, or weight lifting, is great for preventing a slowing metabolism. It offers the benefits of exercise while preserving muscle mass — two factors that affect the speed of your metabolism.

One study with 13 healthy men aged 50–65 found that 16 weeks of resistance training three times weekly increased their BMR by 7.7%

2 – GET ADEQUATE SLEEP

Poor sleep performance and duration will seriously affect bodily processes.

• Decreased hormone function; testosterone/estrogen
• Increased cortisol (stress hormone)
• Reduced energy levels

To name a few. Each of these will result in less movement, reduced ability to retain or develop muscle and create cravings for calorie dense foods

3 – INCREASE PROTEIN INTAKE

Inadequate levels of protein in your diet will accelerate the loss of muscle mass. Resulting in a reduced BMR. Protein also requires more energy to breakdown, thus, increase your TEF component.

4 – TRY GREEN TEA

Research has shown Green Tea can increase your metabolism by 4–5%. This is because green tea contains caffeine and plant compounds, which have been shown to increase your resting metabolism. A study in 10 healthy men found that drinking green tea three times daily increased their metabolism by 4% over 24 hours.

5 – INCREASE NEAT

Move more, burn more. Keep your energy output high in order to maintain a healthy BMR. Your heart, lungs and internals will thank you!

Conclusion

Research shows that a slowing metabolism is inevitable and a natural process. However, the rate of this slowing process varies from person to person based on activity levels, food consumption and ability to maintain/build muscle mass.

We can see how metabolism slows down and understand what can be done to reduce this impact. The good news is that we are somewhat in control of the rate of slowing. Focus on sleep, activity and food consumption and you’ll be fired up and keeping the trim physique well past your ‘prime’ years!