View on GitHub


I know what you’re thinking

“Seriously?  Exercise can’t be bad for weight loss! That’s ridiculous!  It burns calories, and more calories burned means more weight lost!”

Strictly speaking, of course that’s true.  The problem is that exercise ends up having secondary effects that make it counter-productive if your goal is significant weight loss.

Kevin seems incredulous

This certainly sounds like heresy if you look at the modern push for weight loss.  From gym memberships to wearable devices like FitBit, there is a lot of focus on exercise being the primary path to weight loss.

The proposal here is that someone with a significant amount of weight to lose should look at 2 different phases they want to go through:

  1. losing weight, specifically, lowering body fat % (since we want to preserve as much muscle tissue as possible) and then, only after you’re at a healthy body fat percentage,
  2. focusing less on weight and instead on fitness

It’s this second phase where exercise can be much more useful.  The discussion here is how exercise can be problematic during that first phase.

In other words:

  1. Fix your food intake to get to a normal size, and THEN
  2. Exercise to get fit

Exercise DOES have non-weight-loss benefits

Reason #37 why we want to preserve muscle while losing weight

First, let’s get this out of the way, since I’m sure there’s a set of readers that are just waiting to yell at me if they got this far.

Exercise certainly has many benefits, and I’m not saying people should actively avoid exercising. Exercise, especially things that are fun for you, can be good. Do things that you *want* to do. Anything that feels like a chore should be avoided, as it’s going to deplete your limited reserves of willpower.

Exercise has a big upside for health beyond potential weight loss. Many studies and reviews detail how physical activity can improve outcomes in musculoskeletal disorders, cardiovascular disease, diabetes, pulmonary diseases, neurological diseases and depression. The Academy of Medical Royal Colleges declared it a “miracle cure” recently – [New York Times]

Exercise distracts you from the food changes needed

I'm not saying exercise is evil. He looks fabulous!

First and foremost is the problem of mindset.  People think of weight loss as involving 1) diet and 2) exercise.  The problem is that people that believe exercise is more important than diet are the ones that tend to be heavier and eat worse.

“What surprised me the most was the fact that we found lay theories to have an effect on BMI over and above other known factors, such as socio-economic status, age, education, various medical conditions, and sleep habits,” says McFerran.

The researchers hypothesized that the link between people’s beliefs and their BMI might have to do with how much they eat.

A study with Canadian participants revealed that participants who linked obesity to lack of exercise ate significantly more chocolates than those who linked obesity to diet. And a study with participants in Hong Kong showed that participants who were primed to think about the importance of exercise ate more chocolate than those primed to contemplate diet. [Association for Psychological Science]

Trying to lose significant amounts of weight can be a huge mental barrier, but it’s that much worse when you’re trying to add exercise as part of your weight loss regime.

Homer finds something more his speed

The only long-term way to maintain a healthy weight is keeping your daily caloric intake at the right levels. If you focus on exercise, even partially, you’re distracting yourself from the far more important task of getting your food intake under control.

Once you have a handle on your caloric intake, then you’re going to always be able to lose weight. Even if you have some bizarre medical issue crop up such that your basal metabolic rate is lower than it would be otherwise, you can still adjust your caloric intake to be lower and lose weight. You can lose weight by adjusting your food intake without any form of exercise being added. No matter how many calories your body burns in a day, you can ingest fewer than those and lose weight.

Now, when it comes to the actual food intake changes needed, that’s a different story we’ll address separately.

Exercise stimulates your appetite

The most direct way exercise can be counter-productive to weight loss is in stimulating your appetite, making you want to eat more.

Critical post-exercise training question

While exercise tends to decrease appetite right after a workout, hours later there is an increase in appetite. This effect is more pronounced in women than men, although it still exists when men are maintaining a caloric deficit, which we’d want to do if we’re trying to lose weight.

In men, but not in women, appetite was inhibited after BAL relative to DEF. The results indicate that, in women, exercise altered energy-regulating hormones in a direction expected to stimulate energy intake, regardless of energy status. In men, the response to exercise was abolished when energy balance was maintained. The data are consistent with the paradigm that mechanisms to maintain body fat are more effective in women. [American Journal of Physiology]

Ghrelin [hormone released from exercise] enhances appetite and increases food intake in humans [Journal of Clinical Endocrinology & Metabolism]

While it has long been thought that exercise diminishes appetite, this is not a universal truth. Some individuals find that hard exercise can increase their appetite. Scientists have confirmed that some people have an increased level of appetite hormones that drives eating after exercise. [ Mayo Clinic ]

Immediately after vigorous exercise, appetite decreases, probably because of a temporary rise in body temperature, specialists say. But as soon as body temperature normalizes, appetite goes up. [ The Boston Globe ]

Since we want our focus to be on changing our food intake, the last thing we want is something that’s going to make us crave eating even more food!

Exercise doesn’t burn as many calories as you think

The theory, which often doesn't work out in practice

The sad fact is that even decent amounts of exercise just don’t burn enough calories to be meaningful for weight loss. This is usually stated as something like “You can’t out-exercise a bad diet”. Combined with the potential increase in appetite, people often overestimate how many calories they’ve burned in exercising and then negate it (or worse) by eating more afterwards.

You can see an example of some calorie burn rates for an hour of different exercises in this article on the Mayo Clinic site.

Even the highest entries there barely break 1000 calories, and most entries are at or less than 500. And that’s for doing an exercise for an hour.  Add in the time to get to and from the gym and it can be a huge part of your day.

This leads into the next issue:

Exercise takes time

a modern conundrum

The average weight-loss New Year’s resolution involves getting a gym membership then some amount of time each week exercising there. The problem is that as a culture, we’re pretty busy with things already, and it’s going to be difficult to maintain anything that takes a significant amount of additional time each week to maintain.

In life, unexpected things crop up all the time, so even if you have a three-times-a-week plan for hitting the treadmill for an hour after work, it can be difficult to maintain that as issues arise.

Even ignoring those unexpected events, any exercise that’s not fun for you is going to feel like a chore, and even the exercise that *is* fun can involve dreary drives to the gym and lots of time spent on the non-fun parts of getting to actually doing it.

Exercise is a difficult habit to maintain

Let’s say you’ve started your New Year’s weight-loss resolution and you’re hitting the gym 3 times a week and getting in some cardio / lifting / whatever to burn calories and help you lose weight. You’re able to keep it going 4 or 6 weeks and it starts to become a habit. Even though it takes a decent chunk of time out of your week, you’re doing it and things are going fine.

treadmill claims poor mike wazowski as victim

At some point, something’s going to happen that will require you to skip at least a day or two. Sometimes it’s an injury from the exercise itself (sprained ankle, knees hurting, pulled muscle, whatever). Sometimes it’s an illness (came down with the flu or even a simple cold). Maybe it’s even just a normal vacation (you’re out of town, so you won’t be doing your usual gym routine).

maybe someone at Pixar agrees with me?

Whatever it is, as creatures of habit, humans can find it difficult to get back into maintaining the habit of exercise once something’s interrupted it. Your first few days after an illness you may still not ‘feel up to’ hitting the gym and decide to re-start your routines later. After an injury you may give yourself a little more time to recover in the hopes of preventing the injury from reoccurring.

Whatever the situation, any habit like exercise, especially one that takes significant time and effort, will be difficult to get back into once something has happened to interrupt your routine. It’s just simple human nature, and if you’re already feeling bad from an illness or injury, adding guilt on top of that from missing your gym sessions is only going to make you feel worse.

Exercise takes some of your finite daily willpower

We have a finite amount of willpower each day, and just like gas in a tank or electricity in a battery, it gets lower as we use it and it can run out. When you’re trying to change your food intake, especially early on, you’re going to have to use some, if not most, of your daily willpower into changing your eating habits. If you’re trying to combine that with exercise, you’re either going to cause yourself to eat more after the gym (because you spent your willpower on getting to the gym) or you’re going to end up skipping the gym and feeling bad about it (because you spent your willpower earlier on the self-control with food).

These results suggest that the self’s capacity for active volition is limited and that a range of seemingly different, unrelated acts share a common resource. [ Psychology Today ]

Because of this, you need to treat your daily willpower as the finite resource that it is and figure out how to ration it throughout your day. When you’re focused on changing your intake of food, that needs to be what you’re going to ration a lot, hopefully most, of your willpower towards.


As stated first, exercise does certainly have physical and mental benefits to it, and I would never say people should actively avoid it or stop doing whatever they’re currently doing.

The problem comes when you view exercise as a means, especially as a primary means, to weight loss. It’s just a bad focus for your weight loss efforts.  Focus on changing your food intake and get down to a healthy body fat percentage.  Then once you’re down there you can look at exercise as your primary tool: to get fit!

cat tax if you're a cat person
dog tax if you're a dog person