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Are ‘slow’ metabolisms behind the ‘Obesity Crisis’?

[Does having a slow’ metabolism cause weight gain?]

[Does having a 'slow’ metabolism cause weight gain?]

What you’re in for - 1000 words
                             - 7-10 minutes reading time

Why are we having an obesity crisis?
This is the great health question of our generation.
Many arguments have been made and presented in response to the ever-growing concern about our health and that of our children. Sugary drinks, the excessive consumption of carbohydrates, ‘good’ calories vs ‘bad’ calories. 

Some arguments are more relevant than others.

What’s clear is that with 61.7% of the United Kingdom's population being either overweight or obese (1) and so much fog around the cause of obesity, a much needed solution has yet to be found.

In this article I’ll be examining the argument that ‘slow metabolisms’ are the root cause of obesity and weight gain.

So, buckle up, because we’re about to tumble down the rabbit hole...

What is ‘Metabolism’?
Firstly, it’s important for us to define what our metabolism actually is. We can do this by splitting it up into four sections;

RMR (resting metabolic rate) - This makes up the amount of calories or energy used during periods of rest or low periods of activity such a sleeping, or likewise, watching Netflix when you should be sleeping.

NEAT (non exercise activity thermogenesis) -
This component of metabolism is everything in between total rest and absolute activity. Think walking, maintaining good posture and if you’re one of those really annoying co-workers, fidgeting.

The curve ball with NEAT is that it can vary between 15-50% when it comes to making up an individual's metabolism! (2) But more on that later.

EAT (exercise activity thermogenesis) - You guessed it. This is the amount of calories we expend or burn performing physical exercise.

TEF (thermic effect of food) - Finally, it takes energy to digest the food we eat. Ironic right? It costs calories to eat calories. The amount of energy we burn digesting food falls under this bracket of metabolism.

It’s these four components that make up how much energy we burn on a daily basis, or as the people in lab coats like to call it, our total daily expendable energy.

This total daily expendable energy is important, because it determines the “energy out” side of the energy balance theory. 

Break down of daily activityDiagram courtesy of James Krieger,

In order to lose weight, we need to enter a deficit of calories or energy.
In order to gain weight, we need to enter a surplus of calories or energy.

If you bring in more energy than you expend, you’re likely to gain weight.

Energy in, versus energy out.

How do ‘normal’ weight individuals and obese individuals’ metabolisms differ?
If our differing metabolisms do play a fundamental role in the cause of obesity, it’s important that we identify which of its four components are to blame. 

While it’s common to assume that it’s our resting metabolic rate (RMR) that dictates whether we’re under or overweight, and more often or not this is the component often referred to when we speak of our metabolism, the research shows us something very different.

While resting metabolic rate (RMR) is variable between people, and even two individuals at the same weight, height and age can have an upper variance threshold of 10 – 15% the difference in RMR between ‘normal’ weight individuals and post-obese persons is frightfully insignificant across the board, estimated at around 100kcal/p/day (3)

What this tells us is that while there may be small discrepancies between the resting metabolic rates between those who suffer, or who have suffered from obesity, a range of 100kcal/p/day is certainly not the cause of excessive weight gain.

If we however, cast our eye across the non-exercise activity thermogenesis component of metabolism, a very different picture is painted.

The power of NEAT
Rather than large differences in resting metabolic rate between ‘normal’, obese and post-obese persons, the largest difference in energy expenditure can be found within NEAT.

In fact, person to person this component can vary immensely, in some cases up to 2000kcal per day! (4) 

That is a lot of energy, and it would significantly alter the energy balance between two people, thus more broadly promoting either a caloric deficit, or a caloric surplus. In real terms this is the difference between entering a period of weight loss or a period of weight gain.

The real kicker is that despite RMR being relatively similar across the board in ‘normal’, obese and post-obese persons, NEAT tends to be much lower in the obese population.

It’s important to stress here that it’s ridiculous to take this data and jump to the conclusion that those who have entered an obese category are simply ‘lazy’, as a lower NEAT count has been found to have many contributing factors.

‘Compensators’ for instance may see a reduction in NEAT after performing resistance exercise in an effort to conserve energy, which has been found to be driven at biological level, not psychological. (5) 

So what does this mean for my metabolism?
What we can take from this is good news. 

While it’s entirely possible that an individual's RMR could be unfavourable towards losing weight (which studies such as the recent ‘Biggest Loser’ made headlines with), if the largest discrepancies in metabolic differences come from NEAT, rather than RMR, then we have a real chance to reset the balance.

While of course it is folly to presume a disease as complex as obesity can be cured simply by ‘moving more’, research has shown us that it’s possible to make significant changes in body composition by including habits as simple as reaching 10,000 steps per day. (6) 

Rather than focusing on trying to increase RMR, which even with some of the most intense protocols only yield small increments, our time and effort would be far wisely spent doing all we can to increase NEAT.

We can increase our metabolism simply by moving more. Forget green tea tablets, moving more and being active, is the cheapest, most effective metabolism booster you’ll find.


Are some metabolisms slower than others? Entirely possible.

Should I focus on trying to increase my resting metabolic rate? Absolutely not.

Where can I better utilise my time and effort to boost my metabolism? Aim for 10k steps per day (approx.5 miles), and limit the amount of time you spend sitting down or are sedentary as often as possible.

Obesity is a complex topic and a frustrating journey for a great many people. There is however hope for those who are under the impression that their metabolism is ‘broken’ or simply ‘slow’.
The chances are, even if your resting metabolic rate is lower than is optimal, it’s still entirely possible to make positive lifestyle changes through low grade, daily activity and monitoring a calorie reduced diet.

And if you happen to be reading and suffering from obesity...
Know that it’s not easy, and each journey comes with it’s own setbacks and obstacles, but be empowered in the knowledge that you can change.
You are not broken. You are not alone and you can do this.

If you’d like to chat, go hit that email button and let’s grab a coffee. It’s on me. When I’m not writing, I can be a great listener. 

1. 2013, “Statistics on Obesity, physical activity and diet:England 2013” The Health and Social Care Information Centre
2. 1986, Ravussin et al. “Determinants of 24 hour energy expenditure in man. Methods and results using a respiratory chamber.” Journal of Clinical Investigation Dec; 78(6): 1568-1578
3. 2008, Rosenbaum et al. “Long-term persistence of adaptive thermogenesis in subjects who have maintained a reduced body weight” American Society for Clinical Nutrition
4. Black et al., 1996
5. Di Blasio et al., Menopause, 19(1):23-32, 2012
6. 2006, Schneider, PL et al. “Effects of 10,000 steps per day goal in overweight adults” American Journal of Health Promotion Nov-Dec;21(2) 85-9 

Posted on 11th January 2017, 10:38 AM by Owen HendersonReport this post
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