Maybe exercise isn’t as effective for weight loss as you thought
A new study (Careau et al., Energy compensation and adiposity in humans, current biology (2021)) has been doing the rounds on social media this week, so I thought I’d put a quick post together to discuss the findings and implications of this for MOST people. First off, this paper provides some hugely valuable insights into weight loss, and should be a consideration for all coaches working in the weight loss space. In fact, the main concept should be common knowledge for everyone looking to take control of their own health, and that’s the reason for this article.
HOWEVER, before we get lost in the headlines, there’s a couple of points we need to make so the paper has a POSITIVE impact in this space, and isn’t completely misused and manipulated to give a false impression that exercise is LESS beneficial than we thought, so here’s a quick summary of my first thoughts.
Before we get to the context, here’s the key points
The paper offered support for an idea which is known by most practitioners in the weight loss space: that simply “adding” exercise isn’t enough to optimise weight loss success.
It also offered an indication as to why, beyond the fact that our appetite may increase to compensate for Activity Energy Expenditure (AEE). The findings demonstrate that across board, we see a downregulation of Basal Energy Expenditure (BEE) when AEE is increased.
So, what does this mean?
Simply put, this means that all the “extra” Calories we burn off through exercise don’t automatically translate into more Calories burned in our Total Energy Expenditure (TEE). In fact, over 25% of them seem to be compensated- and considerably more (over 49%) in those with the highest levels of bodyfat!
Even more interestingly is the suggestion that this downregulation is a product of BEE. We’ve known for a while that appetite may increase as a compensatory mechanism to maintain weight, and that activity in other areas of the day may reduce, so this seems to be another reason why simply adding exercise will never be enough for consistent weight loss results.
Now, from an evolutionary perspective, this probably makes perfect sense: If food is scarce, then we want to conserve energy. However, in today’s world of abundance of food and sedentary day to day lives, this maladaptation could be causing serious challenges to our ability to take back control of our health.
So, let’s dig a little deeper into why exercise is STILL critical to live a healthy life, and why you should be careful not to fall into the trap of “diet is all that matters” when it comes to weight loss.
#1 The 27% compensation
So, the first crucial point here in favour of exercise. A 27% compensation is still a 73% increase in energy expenditure. Now of course, this can be offset further by compensating with additional food, or reducing activity levels, but if we control for these factors (as any reasonable weight management plan should), then even in it’s crude oversimplification of exercise as just AEE, we’re still more likely to achieve weight loss via a Calorie deficit if we include exercise.
Common knowledge for a LONG time has been diet and exercise is the most effective strategy for weight loss. Don’t miss the big picture.
#2 Exercise adaptations for LONG TERM weight management
The findings here are looking at the snapshot of what happens to our BEE in relation to AEE and TEE. In this context, exercise benefit is defined solely as Activity Energy Expenditure (AEE). With that in mind, it’s no surprise at all that exercise here shows limited benefit.
However, let’s step back from the micro, and take a macro view of exercise.
The right type of exercise can drive a whole range of adaptations that are likely to improve our ability to manage weight; including physical changes and physiological changes (mitochondrial biogenesis, cardiopulmonary adaptation, improved hormonal regulation and sensitivity, increased strength and muscle function, improved metabolic flexibility, and more), psychological changes (better mood, less stress, improved confidence, better sleep, more considered decision making, etc) and more!
Simply put, exercise is more than just Calories burned- the adaptations may take time, but exercise IS a magic pill when it comes to heal benefits.
That said, in the context of weight management, we want to be efficient- and beyond this, manipulating nutrition to ENHANCE these adaptations is absolutely the best approach.
So, once again, it seems for weight management (and health/ fitness benefits…) diet AND exercise is the best approach.
#3 Are some of us predisposed to be more fat and less healthy?
The study points out an interesting observation that those with the highest bodyfat % appear to also have the largest compensation in BEE. This suggests that those with the most need for weight loss, are likely to struggle the most from adding activity.
This begs an interesting question. Are some people just pre-disposed to be overweight and unhealthy? Or is it that the more out of shape we get, the harder it is for our body to recover?
This is for future research to determine, but I’ll make a prediction here.
It’s both- but that absolutely doesn’t mean you’re not in control.
We know that genetics and other factors- including environment- play a huge role in our health and weight. I’m sure you’ve all met the person who seems to always be in shape, and gets results straight away when they kick it up a notch.
And I’m sure you also know someone who seems to be the opposite: it’s hard for them to lose weight, and it seems everything is working against them when they try to pick up exercise or diet.
So, yep, genetics and other environmental factors beyond your control almost certainly have an impact on your weight and health.
That said, the BIGGER impact is probably amongst the things you can control.
We know that weight gain is a product of consuming more energy that you use- for whatever reason. We know that strategies to create an energy deficit will lead to weight loss- this isn’t simple to do, but it’s certainly the case. We know that exercise has incomparable health benefits across board.
So, whatever your genetic predisposition, I’m confident to say that you’re not doomed to be overweight and unhealthy- you can make progress towards better health, better movement, and better fitness.
I may have mentioned, but the best way appears to be a combination of diet and exercise.
Final note on exercise and weight loss:
An interesting comment in the paper is the consideration that those who are most overweight and show the largest compensation between AEE and BEE may actually be consuming the least food, leading to increased metabolic adaptations the conserve energy.
What the paper doesn’t directly discuss is the impact of nutritional interventions on BEE. Now, energetics of exercise sessions vs daily movement: even when we equate for Calories, are probably very different- so I for one wouldn’t expect the effect to be equal. However, we do know that metabolic adaptation from extended or extreme energy deficits occurs: it’ll be interesting to look at where the two ideas of compensation and metabolic adaptation overlap, and how this can further inform our weight management plans in the future.
So, as a final comment, I’ll adjust my guidance.
It seems that the combination of an APPROPRIATE DIET and APPROPRIATE EXERCISE are the key to weight loss.
Lucky for me, it seems my job as a coach/ personal trainer is safe- and not only does exercise matter, but it also helps if you know what you’re doing.
Here’s a link to the paper I’ve been discussing today:
Josh Kennedy MSc, ASCC, CSCS