What does that even mean? Exercise burns calories much faster than inactivity. Less calories means less fat.
If you intake X calories, your body will use them to provide you energy for exercise. If you don’t exercise, you won’t always just turn it into fat - your body will find another find other uses of the calories such as producing stress hormones.
Exercise is important but will not make you lose weight alone.
The saying is you can't outrun a bad diet.
- one, your body may crave more food because of the energy loss - the Lipostat model suggests that your body has a target weight (well, fat level, more precisley), and will adjust hunger up if calory expenditure goes up
- your internal processes use way more energy than you can consume through exercise in a modern lifestyle (2000+ calories a day just from sitting still, for many adult males), and there is a lot of room for the body to adjust those up and down to make up for the extra exercise to keep up your current weight. So if you consume 2000 Cal a day with 0 Cal from exercise, with moderate exercise you will end up conauming 1600 Cal a day from internal processes + 400 Cal a day from exercise after some time (a one time run will absolutely consume extra, if your run every day, you'll get less and less extra Cal from your runs, until you reach about net 0, assuming you're not increasing the amount of exercise constantly).
Diet is and always will be the key to weight loss.
At one stage, I started walking home from work at my fastest pace. 5 miles, 5 days a week. No other lifestyle changes. No significant weight loss.
A few years later, I started tracking calories with myfitnesspal and keeping to a limit (1600 initially, 1400 when it became easier). No exercise, but steady and impressive weight loss. I seem to have kept most of it off. I think a lot of it becomes psychological - not being afraid to feel appetite or skip meals if already satiated from earlier.
> While you're right that exercise can help on the margin, it's just not a useful intervention that moves the needle much as far as weight loss goes.
There's more to exercise than just the thermodynamic effects of calorie expenditure. Building muscle and/or cardiovascular capacity will improve your quality of life and will complement any weight loss. You can improve your mental health by becoming more physically active, and this is well established. Those mental health gains and physical health improvements make it easier to maintain a better diet. Beyond the marginal, but significant calorie expenditures you can create a positive feedback loop.
Not to mention, the processes in your body are way more complex than all this makes them out to be. For moderate exercise, after an adaptation period of a few weeks to months, there is almost no calorie impact from the exercise itself on your total calorie expenditure: your metabolism adjusts and various internal processes are deprioritized to prioritize the exercise.
This is in fact a major component of why exercise is so healthy: it doesn't do much for weight loss, but it stops/slows down all sorts of unnecessary processes in the body that are actively harming your overall health.
This is categorically false. You don’t have a magical metabolic adjustment, you simply become more efficient in performing an exercise but the calorie use never drops to effectively zero like you’re claiming. Think about this for a second, it makes no sense to think that running could ever consume zero calories, basic physics still apply.
- no exercise vs moderate exercise vs athlete-level exercise are very different cases. Doing some exercise does increase total energy expenditure vs no exercise, but the amount doesn't change significantly until you get to pro-athlete levels. That is, going from 2000/0 Cal (BMR/exercise) to 200 Cal of exercise might take you to, say, 2100/200 Cal; but moving from 200 Cal of daily exercise to 400 Cal of daily exercise will not take you to a higher TEE; unless you reach the stage where you are doing, say, 1000+ Cal worth of daily exercise (specific numbers pulled from thin air, just trying to illustrate the concept).
- Muscle mass is a confounder for what I was claiming - more exercise leads to increased muscle mass normally, and that does lead to an increase in BMR very directly.
Overall the more correct claim I should have made would be "exercising more, assuming you are not very sedentary, will not lead to increases in total energy expenditure beyond those gained from muscle mass increase, unless you get to pro athlete levels of exercise".
Here are some studies backing me up:
- https://journals.physiology.org/doi/full/10.1152/physiol.000...
- https://onlinelibrary.wiley.com/doi/10.1002/ajhb.22711
- https://www.cell.com/fulltext/S0960-9822(15)01577-8
I'm taking all of these links from the Kurzgesagt sources for their video on exercise: https://sites.google.com/view/sources-workoutparadox. They link to more specific claims from each paper, and to a bunch of other papers.
And likely already at a low body fat otherwise it would be crippling for your joints.
Most people can walk 30 mins but I would doubt if most can run a marathon.
Nitpick: a marathon is 42 kilometers (by definition). Most people would struggle to even walk that.
The insane efficiency of the body is the problem.
30 minutes of agony -- the jog -- can be thrown out the window with literally one minute (60 seconds) of overeating.
That's why I think exercise plus GLP-1 medications once a year might be the future gold standard for weight loss and maintenance.
Any thoughts on GLP-1 meds being the game changer we need?
GLP-1 are crutches and if you need it once a year.
Aging is rough.
And the high calorie to nutrient ratio in this country makes it really hard to avoid adding pounds.
This country is calorie and diet obsessed, and yet average weight seems to keep increasing.
if you are already meeting that baseline, and still have issues, then you should look at tweaking other variables in the equation, whether diet, stress, etc.
What I find worrying is the cherry picking some people do, e.g. "aha your body will get used to exercise, so I might as well not bother", then wonder why at their next visit to the doctor, they are now told to go on a steady diet of statins etc.
That doesn't mean exercise isn't extremely important for your health. It is, in a myriad ways. Even the mechanisms that make it not help with weight loss are some of the reasons why it is so healthy - it's taking away calories from metabolic processes that are more harmful than helpful.
I only see that study cited by people who are looking for excuses to not exercise.
At the same time, I keep up with the latest science and understand the limitations of exercise as a means of sustainable weight loss for the general population.
Please stop talking about simple arithmetic - the body is not a simple machine and trying to conceptualize it as such is willfully ignorant.