Exercise is the foundation of fitness.
It makes us stronger.
It gives us energy.
It makes us feel good about ourselves, especially in the mirror.
Of course, unwanted challenges of exercise exist as well, like getting our muscles sore
or bringing up dread when we don’t hit a new bench PR for a few days.
Or, it makes us hungrier?
Some people’s experience, maybe even your own, might have you believing that exercise
makes you hungrier.
Exit the gym, the first thing you think about is finding the closest place to fill your
face with carbs.
However, as we like to do around here, instead of leaving it to personal anecdotes, which
to be fair has its use case, we more wanna know, WHAT does the science say?
And, for that, the science does suggest your GUT feeling is… probably wrong.
When looking for data about this, we simply wanna find studies that looked at hunger and
appetite outcomes with the presence of exercise versus sitting on your booty.
We also wanna see its potential impact on total calorie intake.
IE, whether exercise led to more food eaten.
With this in mind, a fair amount of research does exist, many of which are also recent
and can help us come to a decent conclusion.
The first being a 2017 study where subjects were trialed in either 0, 15, 30, or 45 minutes
of intense aerobic exercise on a cycle ergometer.
The researchers found that subjective appetite nor total food intake differed between trials.
In other words, whether they did no exercise all the way up to an intense 45-minute cycling
bout, there were no changes in feelings of hunger.
Another interesting finding was also that more exercise did not result in consuming
more calories than regular.
So even if you did feel hungrier from exercise, it wouldn’t be too bad since it wouldn’t
lead you to eating more food to compensate for the extra calories burned.
An important limitation of this study however, is that it only tested male subjects, so this
data won’t tell us whether there are any sex differences.
Data in 2016, however, by Howe and colleagues, did look into the impact on female subjects’
appetite with intense exercise, this time with varying intensities of running on a treadmill.
The research found that intense aerobic bouts in women did have an impact on appetite, but
interestingly, it actually trended towards the opposite direction.
Appetite, in fact, was slightly suppressed post-exercise.
This finding of appetite “suppression” was actually the trend in MOST of the research.
And yes, this applies to resistance training as well.
In fact, it was a stumbling upon on a newly released 2021 study that made me think about
making this video in the first place.
Interestingly, the new study found that full body resistance training had more of an impact
on reducing subjective hunger ratings than just doing either upper or lower body training.
If you want me to take a deeper dive in this study specifically, please let me know in
the comments.
Fittingly, we culminate the consensus of this matter through nothing other than a fancy
shmancy 2014 meta-analysis.
20 total studies were analyzed, involving 241 subjects, majority being men, ranging
from many different training levels, BMI, and types and duration of exercises performed.
It was a good, mixed bag of research that covered a … decent amount of populations
and training forms to draw a consensus.
And the consensus, again, was clear.
Although they did not set out to analyze subjective appetite and hunger levels like we saw with
other research, they did look into relevant hormones that are known mediators of appetite
regulation.
In doing so, it might better help us understand why people have less of an appetite after
training.
In their analysis, they found that after exercise, levels of something called acylated ghrelin,
a peripheral hormone known to stimulate hunger, decreased.
On the other hand, known mediators in reducing food intake, such as PYY and GLP-1, increased.
And even though this was an analysis in 2014, newer studies pretty much follow the same
conclusion.
This basically means, after exercise, a hormone that makes you hungry is reduced and hormones
that make you wanna eat less is increased.
A two-way attack on suppressing hunger, which is a potential benefit to those trying to
lose weight.
But of course, for all transparency, there is a limitation to this meta-analysis.
The studies analyzed here were all acute in nature, aka they were short-term studies.
Because of that, it’s not clear if exercise has a long-term impact on one’s appetite
related hormones.
In addition, although this is not exactly a limitation of the study itself but rather
looking at the big picture, hormones are only, as the researchers put it, “one aspect of
a complex system that regulates human feeding behavior.
A number of other variables related to exercise have been shown to influence food and beverage
intake.”
Not too get too into these other variables in this particular video, but there are things
like visual stimulation after exercise, like seeing your favorite burger joint right across
the street from your gym, or you already expecting some delicious meal as your reward for going
to the gym in the first place.
Having these other factors present might sway one’s appetite pendulum to the other direction
regardless of these changes in hormones.
Alternatively, it can just simply be that you haven’t ate anything in a while before
going to the gym.
Certainly, these slight changes in your hormones aren’t going to do much to influence your
natural, satiation needs.
Okay, now to summarize it all: Exercise does not seem to increase appetite
or hunger, at least not by itself.
Exercise is more likely to reduce subjective feelings of hunger.
Exercise can suppress hormones like acylated ghrelin, which increases appetite, while increasing
hormones like GLP-1 and PYY, which mediates food inhibition.
Other environmental factors might still play a role that can increase your appetite regardless
of these aforementioned effects.
As for real-world and practical use of this information: Since exercise doesn’t seem
to do much to your hunger, there’s really nothing for you to do other than stick to
whatever nutrition and exercise plan you have.
Whether you feel hungrier, less hungry, or anything in between after training, it’s
all good.
You’ll… be fine.
If you enjoyed this video, please make sure to like it and share it with your hunger-loving
friends.
Feel free to subscribe for more videos just like this.
And as always, hunger suppressing or not, make sure to GET YOUR PROTEIN!