To explain that exercise does not affect your weight, or impact on obesity rates

[allmyown]

I see this misconception all over MN every day.

Exercise is fantastic for your physical and mental health in many ways, but it is not a weight loss tool.

Posters are forever quoting energy in -minus energy out = energy stored, etc, as if we are petrol engines or something! we are not - this is not how our body works.

It is more like energy available / energy required to maintain weight= energy body decides to use.

Your body burns off excess energy if you are taking in more than your homeostatic systems think you need. Your body slows down and uses far less energy if you have taken in less than your homeostatic system thinks you need.

And so if you lose weight, and go below what your body wants you to be, then your metabolism will just slow down massively to make the weight go back on. And if you exercise a lot, your metabolism will just adjust to accommodate that.

The key to weight loss is making sure your homeostatic systems decide you should be a healthy weight. You can lower the weight your homeostatic systems is attempting to maintain, with healthy eating, cut out sugar, HPF, vegetable oil, margarine, and cut down on wheat.

Eat plenty of fresh food and greens, nothing long dated.

Unless you are running 10K every single day, you are not exercising enough to change your weight, and even if you are, it won't stay changed.

The obesity epidemic is related to sugar, highly processed food, vegetable oil, margarine, etc, and poor diet in general, not too little exercise.

But don't get me wrong, there are other health problems caused by too little exercise, I am not saying exercise is bad, just that an obese child is not necessarily a child getting inadequate exercise, as so many people seem to think.

Read "Why we eat too much" by Andrew Jenkinson, he explains the up to date science in so much more detail.

so an exercise sessions is a tiny percent of calories used up in a day, and your BMR just drops to compensate.

So why do athletes need more calories to maintain their weight than people who don’t exercise?

Several people have asked this but you’ve not answered.

For everyone wondering where this has come from, this is a good place to start (including a segment about why office workers burn the same calories as hunter gatherers)

https://www.bbc.co.uk/programmes/articles/5JnKXqn75gBQbqXJwj9wgN0/how-much-exercise-should-you-really-be-doing

Like I said before, I'm too old to buy readily into any new theory. But, if you're interested in this, I think it's worth actually having a read/listen to the series, and keeping an open mind.

Most diet books are based on some fairly shaky science. They seem to be based off the premise that loosing weight is complex. They are at the end of the day designed to sell and make money.

Fundamentally if your energy expenditure is more than your energy intake you will lose weight. If your energy intake is higher than your expenditure you will gain weight.

Theres obviously varying amounts at how we absorb energy from different food products and we can alter our basal metabolic rate in differing ways. Also other means we can trick ourselves into feeling full and reducing appetite. None of these however take away from the fundamentals.

Unfortunately loosing weight is hard, it requires a continual energy intake deficit. It isn’t however as complex as half these books make it out of be.

The theory would say that actual athletes are burning so many calories that their metabolism can't compensate. They also tend to train over many hours throughout the day. Regular people often do an intense 20-30 minute workout, then go into "energy saving mode" without realising (standing up less often, walking about less etc).

Yes, but same goes with food. As you drop weight you have to restrict more to lose more weight as you become a slimmer person.

Haha, sadly I can confirm that even training for ultra marathons isn't a good way to lose weight! I'm not overweight but could do with losing two or three pounds.

Haven't had time to read the whole thread yet but this is a really interesting area. I studied biology (although relatively weak on physiology) and follow some of the running related exercise science. The Koopcast and Science of Ultra are great for this.

This may have been mentioned already but most people seem to be able to 'absorb' around 600 calories of exercise. This feels roughly correct based on my n of one - I expend probably around 1k calories per day on average running and walking briskly. I eat some extra snacks compared to inactive periods but it's unlikely to be more than 400-500 extra calories (I don't track calories).

Another aspect I find fascinating is that the first things that get turned off to keep calorie expenditure level are inflammatory and stress responses. This would explain some of the health and wellbeing benefits of exercise. Herman Pontzer is a researcher who has published a fair bit on this.

This systematic review of Role of Physical Activity for Weight Loss and Weight Maintenance is interesting. Extracts from it:

“ Most, but not all, study data indicate that exercise alone plays a very small role in weight loss. A joint position statement of the American College of Sports Medicine and the ADA (12) states that the “recommended levels of PA [physical activity] may help produce weight loss. However, up to 60 min/day may be required when relying on exercise alone for weight loss.”

“There is also evidence to support the notion that individuals who are less physically active are more likely to gain weight over time than those who exercise between 150 and 300 min/week (25).”

“Physical activity may be an important component of weight maintenance after weight loss. An excellent study that measured total energy expenditure with the doubly labeled water method suggested that physical activity in the range of 11–12 kcal/kg/day (900 calories/day for an 81-kg woman) may be important to prevent weight regain (20). In the NWCR, 90% of participants reported exercise to achieve long-term weight loss maintenance, with an average 383-calorieenergy expenditure 7 days/week”

“Conclusion

The evidence that exercise contributes significantly to weight loss and weight maintenance is not firmly established. It is important to recognize the challenge of monitoring dietary intake and exercise intensity and duration over the long term. Overreporting of actual exercise and underreporting of food intake by individuals could be a contributing factor to the mixed results found to date. In addition, individual differences may play a role (responders vs. nonresponders). Variability in sex, BMI, exercise intensity and duration, and type of exercise in research studies make conclusive recommendations more difficult. Minimal research has been focused specifically on the weight loss effects of exercise alone in individuals with type 2 diabetes, who may have a different response to exercise than the population without diabetes.

Consistently performing exercise of a duration greater than the basic recommendations for health (150 min/week of moderate-intensity exercise) does appear to be more likely to contribute to weight loss and weight maintenance efforts over the long term.”
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5556592/

I think mood, food choices, exercise, hormone profile and metabolism are all inextricably linked. There are all sorts of things beyond food in and out which affect the metabolism and thus the way the body processes energy from food, all sorts of things which affect food choices in the first place, and all sorts of things which affect energy levels and thus motivation for exercise. I think on that basis it’s unhelpful and wrong to claim it’s only about what you eat and nothing to do with exercise or anything else. You can’t isolate food as the sole factor- that’s as faddy as claiming you can exercise your way to thinness.

Yep, height and weight are important in how many calories you can consume. It sucks to be me because I could quite happily consume 3000+ calories a day if I just did what I wanted. Probably wouldn't exercise half as much either.

However I'm very short and also slowly reaching the lower end of a healthy BMI so my calorie allowance without exercise is impossible. Even with the shit ton I actually do it's manageable to lose weight and more manageable to maintain but it still sucks when I'm craving a McDonald's double quarter pounder with cheese meal.

@allmyown I actually agree with you.....I'm overweight, but physically active..... However my diet is awful
"You can't outrun a bad diet".....

I don't suppose you have any easy or non- obvious tips on improving a diet?

....except that the spring I broke my ankle and couldn't run, the weight stayed on until I could exercise.

It's no good OP. Your body reacts in one way. Other people aren't necessarily the same. Genetics will play a big part.

The OP is nonsense. Of course exercise has an effect upon weight, as both the vast weight of scientific evidence and people's anecdotal experience here attest.

There is some evidence of metabolism adjustment, particularly in the early stages of a weight loss regime, but not of such significance that it negates the effect of exercise altogether.

It has to be the right kind of exercise. Substantial amounts of cardio can burn a lot of carlories. Weight training, by and large, doesn't (though it of course has other benefits).

And of course it's all tied up with diet (calories in). Eat enough crap and it won't matter how much you exercise.

I heard Jenkinson on a podcast but some of what he said seemed to contradict his own position, and I'm not willing to erase an entire body of scientific knowledge of wide consensus built up over centuries, just because of one book.

OP could you respond to me please as I have been pondering this since I first read your posit and am now worrying a bit. If exercise doesn't lead to weight loss, but my calorie consumption hasn't changed, I probably need to arrange a check up to find out why I am losing weight.

Doublehelix, I just looked up Herman Pontzer, interesting work. Found this:

“He backed this up with a new analysis of data from another team’s study of sedentary women trained to run half marathons: After weeks of training, they barely burned more energy per day when they were running 40 kilometers per week than before they started to train. In another study of marathoners who ran 42.6 kilometers daily 6 days per week for 140 days in the Race Across the USA, Pontzer and his colleagues found the runners burned gradually less energy over time—4900 calories per day at the end of the race compared with 6200 calories at the start.

As the athletes’ ran more and more over weeks or months, their metabolic engines cut back elsewhere to make room for the extra exercise costs, Pontzer says. Conversely, if you’re a couch potato, you might still spend almost as many calories daily, leaving more energy for your body to spend on internal processes such as a stress response.

This is Pontzer’s “most controversial and interesting idea,” says Harvard paleoanthropologist Daniel Lieberman, who was Pontzer’s thesis adviser. “This morning I ran about 5 miles; I spent about 500 calories running. In a very simplistic model that would mean my TEE would be 500 calories higher. … According to Herman, humans who are more active don’t have that much higher TEE as you’d predict … but we still don’t know why or how that occurs.”

Pontzer’s findings have a discouraging implication for people wanting to lose weight. “You can’t exercise your way out of obesity,” says evolutionary physiologist John Speakman of the Chinese Academy of Sciences. “It’s one of those zombie ideas that refuses to die.” Already the research is influencing dietary guidelines for nutrition and weight loss. The U.K. National Food Strategy, for example, notes that “you can’t outrun a bad diet.”

But Thyfault warns that message may do more harm than good. People who exercise are less likely to gain weight in the first place, and those who exercise while they diet tend to keep weight off better, he says. Exercise also can impact where fat is stored on the body and the risk of diabetes and heart disease, he says.

Pontzer agrees that exercise is essential for good health: The Hadza, who are active and fit into their 70s and 80s, don’t get diabetes and heart disease. And, he adds, “If exercise is tamping down the stress response, that compensation is a good thing.” But he says it’s not fair to mislead dieters: “Exercise prevents you from getting sick, but diet is your best tool for weight management.”
https://dupri.duke.edu/news-events/news/calorie-counter-evolutionary-anthropologist-herman-pontzer-busts-myths-about-how

The problem with just restricting calorie intake is that it can reduce muscle mass, thus reducing your overall calorie burn. While exercise alone won’t lose weight, it will increase muscle mass (depending on the exercise type) and therefore your overall calorie burn increases.
I’ve found, particularly post meno, that eating too few calories results in weight gain. I think I’ve got true peasant metabolism and it decides it’s famine time so stores fat for the future. I’m a stress ‘non eater’ ( forget to eat when stressed) so make sure I’ve got protein balls available for a quick calorific snack

Agree

@allmyown

But I hope I have at least raised awareness

You haven't

Metabolic rate increases the more you exercise. Fitter people are more active so you end up burning more calories. And more muscle mass also requires more calories

Yes you would burn less if you sat still all day with a lower metabolic rate. But you don't sit still all day because you're exercising more.

Anyway I don't see any really overweight people exercising. So there's a link somewhere.

@silverneedle that's exactly what I've taken from the scientific debate. It's a relatively new field but the evidence base seems to be getting more solid.

It's a hard message to convey though, and a lot of the nuance can be lost in debates. I don't think any serious scientist or physician would ever discourage someone from exercising to support their health and get to (or maintain) a healthy weight, but it's important to acknowledge that it's not as simple as calories in minus calories out. (And that's before you even get to the difficulties in calculating the 'in' side of the equation with any degree of accuracy)

So running a marathon daily burns around 3000 extra calories , even after your body has adapted to it. So 115 calories per mile.

That doesn't say that exercise doesn't burn calories at all. Obviously whether you lose weight would depend on how much you ate.

Did the athletes weigh the same at the end, did they have the same amount of muscle and fat, and did they run at the same speed? I suspect the answer to these would all be No. So you aren't comparing like with like.

I've lost weight from exercise alone. I also gained weight when changing from an active job to an office job. Exercise is definitely related to weight for me.

This may have been mentioned already but most people seem to be able to 'absorb' around 600 calories of exercise. This feels roughly correct based on my n of one - I expend probably around 1k calories per day on average running and walking briskly. I eat some extra snacks compared to inactive periods but it's unlikely to be more than 400-500 extra calories (I don't track calories).

That's the thing: All these claims about how the extra calories out don't help are based on situations where the other variables aren't measured. Of course if you exercise and then just react by eating more then you won't lose weight.

And one thing we all know is that we tend to underestimate calorie intake when not measuring it carefully. So I'm going to take your rough guesses of 1k calories out from running (that's a LOT of running) and 500 in from snacking with a pretty big pinch of salt.

The only way you can properly measure the role of exercise is by properly tracking the calories burnt as well as properly recording the calories you eat. It may still be true that some of the difference is compensated for by adjustment in your TDEE, in the way you burn calories or don't just milling around your house. But not enough to eradicate the effect of a serious diet-exercise regime followed consistently long term. As shown by the millions of people all over the world who have managed to lose weight and keep it off.

This morning I ran about 5 miles; I spent about 500 calories running. In a very simplistic model that would mean my TEE would be 500 calories higher.… According to Herman, humans who are more active don’t have that much higher TEE as you’d predict … but we still don’t know why or how that occurs.”

"Don't have that much higher TEE as you'd predict" is not the same thing as "don't have a higher TEE at all", which is what the OP seems to be claiming.

Depends what exercise you do surely.

A typical day for me is

30 minutes run is 300 calories
40 minutes walk to and from town is 200.

That's 500 calories so a quarter of my basal requirement.

An equivalent person who doesn't run and drives everywhere will require fewer calories. Ok maybe not 500 fewer but say 400 fewer.

If I now add a day's hillwalking at the weekend, or a 4 hour bike ride, I'm going to burn another 1000-2000 calories just on one day. If I carry on eating the same, I will lose weight. The issue is I will probably feel hungrier so may end up eating more. But that is not a given.

If your exercise is a 20 minute fairly slow walk (probably all that an obese 6 person can manage) then that isn't going to burn many calories no.

On the other hand an obese person who exercises will be much healthier than one who doesn't so it's still worthwhile

If you're only burning 40 calories in a gym session you're doing it wrong.