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.

Who is monitoring the prisoners? The screws? Have you actually been in a prison? 😂

No it doesn't. What happens is you eat more to compensate, unless you are actively trying to lose weight. Your bmr can drop a bit but not that much.

Endurance athletes eat up to 6000 calories a day. And lose weight at the same time

Why are these guys never fat then?

And yet, when I do the long dog walks at the weekend, I drop a couple of pounds. If I don’t, no weight comes off. I’m generally quite active at work, I run round regularly, but no walks at the weekend=no weight loss.

Many years ago, I rode two horses most days, walked the dogs, played badminton against someone who made me run round like a headless chicken and swam 50 lengths on some days. I lost over 8st. My food was very much a factor but the exercise was probably a bit extreme and was definitely the big factor in the weight loss.

Fortunately OP is wrong because being a middle-aged shortarse, I have no intention on miserably existing on my BMR of 1400 calories per day to sustain my weight.

My weight goes up during phases where exercised is reduced, e.g. during injury, or when the reasons for my functional walking became illegal in 2020/21.
I'm usually in balance with a stable weight. I've recently twigged that I've gained a few unnecessary lbs since the autumn because of reduced walking as DS now goes to school independently and the weather's been poor, so I'm adding in short exercise breaks to replace it in a realistic way that doesn't add fatigue on top of my usual exercise plan/ training.

Exercise is important for muscle mass which has a higher metabolic rate than being skinny-fat. Plus the long term health benefits of resisting the decline of muscle mass with age, and bone density, good circulation etc etc.

When I run, it's often over lunchtime. The fuel I eat to keep me going over long runs is less than I'd eat for lunch. After long/ hard sessions, my appetite is often suppressed. I eat less than I would spending more time in the house (another contribution to lockdown gains) Exercise motivates me to eat more nutritious food and to eat protein to build/protect my muscle mass.

For most people exercise isn't the whole answer, but it's a great tool for healthily sustaining weight, and most people gain weight by a gradual over eating over time by small margins, so introducing exercise can be enough to favourably tip the balance for some. Retaining muscle mass through exercise also reduces calorie needs going down as weight is lost as the body loses fat and muscle if food intake isn't adjusted carefully.

And an hour's swimming or running can burn 600.

I've worked out my BMR to be somewhere around 1600 - 1700 calories and the "stuff of life" to add about another 300 bringing that up to around 2000. The OP would have me believe that as a result of swimming for an hour, I spend the rest of my day not only doing literally nothing, but burning several hundred less calories in the way I breathe while (not) do so.

There's nothing wrong with acknowledging that BMR varies and adjusts, and my 600 calories burnt swimming may not equate to a FULL 600 calorie deficit overall. But that's a very different thing from claiming that they're completely wiped out.

The numbers just don't add up. And anectodal experience bears that out.

I genuinely don't understand this. I've lost weight slowly and steadily the last 6 months by first tracking my food and seeing how many calories I ate vs how many my Fitbit says I burned. Then I upped my exercise to create a small calorie deficit across the week, because exercise has lots of benefits for me as well as burning more calories.

Why have I lost weight, if it isn't from increased exercise?

studies have shown athletes have higher BMRs, they’ve also shown certain type of exercise boost BMR for a period of time. You’re stating absolutes that might not necessarily be absolutes. The bottom line is, the only way to lose weight is to be in a calorie deficit (which is why all these stupid diets work then fail, because they’re stupid) and exercise can help you get your metabolism firing. Simply exercising with no diet change is going to take a long time to have an effect, on the flip side simply dropping your calories will give you a quick fairly fast weight loss but your body soon adapts. Bottom line is it’s all about balance, you need both diet and exercise to do that.

It does have an effect on weight, one way it affects your weight Is exercising builds muscle therefore your body uses more energy and calories.

You don’t even understand what BMR is. If you did you would know that exercise is not part of your BMR.

BMR is the calories used to maintain basic bodily functions. Coma calories. Then you’ve got NEAT, TEF and EAT. Planned exercise comes under EAT.

I've read a lot about this. Frustratingly I can't find one bit of research that I always remember but it basically said that around 20% of the population are able to lose weight through exercise. For the rest of us, it's as you say OP, our metabolic rate just slows down while we're at rest and there's absolutely no weight loss at all. Exercise has loads of other health benefits for everyone - the 20% and the 80% alike (as you've said), but it's pointless as a weight loss effort unless you're in the 5th of the population with the right genes. It's completely ineffective for most people. I am one of these people. I could add an extra 9 hours of exercise a day into my life tomorrow (actually tried that in my teens) and keep my diet the same (calorie counted) and it would have no effect at all.

I haven't RTFT but from that comment I don't see any misunderstanding of BMR. You are of course correct in that exercise is not part of BMR but the OP's point is that your BMR is not constant and unchanging (for most of us anyway). If you exercise more your body may well burn more calories for the hour or so that you're doing it but when you go back to resting, your BMR will slow down so that the by the end of the day no extra calories have been burnt. Again these are generalisations that don't apply across the board - we are a very complex species - but there is a lot of science that shows that that's how it works for most of us sadly. If you're not in that unlucky majority count yourself very lucky!

Not true for me. I eat the same foods and lose weight when I exercise but gain/lose less when I don’t.

well, obviously, some things like cutting out sugar are very clear, but a lot of other information that helps with weight loss is less clear, and being informed is very helpful, for example, upf, and margarine causing obesity might not be something you realise unless you are told.

No, you don't need the book, you can look at all peer reviewed research over the last few decades, if you know where to find it, and can buy each research paper separately.

I just mention the book because it lists and summarises it all very neatly

Yes, I work in prisons, and these studies were done by scientists, who employed chefs and other staff to work within the prison for the duration of the study. The results are very clear.

As I said, if you go to extremes, such as running 10 miles every single day, that is the amount of exercise needed to make an impact on weight, but this is only a temporary impact anyway.

Look at studies where BMR is actually MEASURED - not estimated. It can and does vary hugely to compensate, and keep your weight the same

well, you do! and part of the problem is you think you can estimate your BMR, but you can't. If you want to know your BMR, it needs to be measured, in a lab, overnight. And you can't do that, but in studies where it has been done, then yes, the BMR does simply adjust to compensate

I read his book and the next one he wrote with practical tips. They made an interesting read and most certainly go some way to explain how I have managed to eat (and drink) far more calories than I needed when younger and always stay a consistent weight. I have always been active but not intentional exercise. Whilst my diet was not great from a calorific perspective, my diet has also been low in UPF.

He gives a lot of tips in his second book; my main interpretation was to lower your weight set-point requires a gradual permanent change. The general theory of adjusting diet for weight and exercise for shape applies but you need to slowly improve your diet to something that you can continue forever. Following a stereotypical diet book works temporarily but the sudden loss in weight causes problems and the body convinces the brain you need more calories so inevitably put it back on.

I agree with all the PP that staying active and exercising regularly is the biggest motivation to look at what I fuel my body with and results in me eating much better. As someone who spent their younger years eating a lot of high carb meals (mostly wheat) without a second thought, it has taken a gradual shift in mentality for me to pick healthier option

As much as I hate anecdote=data this doesn’t fit with my observations at all. When we were young we had to walk everywhere and we walked to lots of different places during the day. we were all skinny. When we left university and got desk jobs we all put on weight. That’s really common. Sure maybe for some of those people their diets also changed but I know mine didn’t. If anything it probably got a bit better. I got back to that weight when I started running again and if anything I increased my calories. I had to improve the quality of my diet when I got high cholesterol but the weight was definitely driven by exercise.

The fashion is just this upf nonsense

Yeah sure it's unhealthy but you could be thin and eat nothing but

Walked to and from work. Was meant to be for my mental health - it helped - but also lost weight.

OP I think you have misunderstood this.
Our bodies are always trying to conserve energy and after exercise the bmr reduces a bit to try to compensate. But there is a limit to how much it can drop. Otherwise no one would starve to death their bodies would just cleverly burn less energy. Also muscle mass actually increases bmr and over the long term exercise (even cardio) will increase muscle mass.

With an effectively limitless food supply of cheap biscuits etc most people who aren't professional athletes can manage to over eat regardless of how much they exercise. But many people are not massively overeating at all. They just have a very sedentary lifestyle that has led them to slowly gain weight. If they can increase their activity levels and build more muscle mass they will be more likely to maintain a healthy weight.

https://examine.com/research-feed/study/dZN8qd/

I don't think anything about weight loss or gain is simple. Exercise helps in a roundabout way perhaps e.g. makes us feel better so we might not eat the upf or has an impact on insulin resistance or simply when you are exercising you are not eating.

I do think people overly simplify weight gain and loss. Look at the way hormones impact weight or meditation. Social media is full of people telling us - do X or Y and hey presto. There is a doc who then debunks these claims. How can anyone navigate this landscape when there is so much misinformation or partial information about.

I think people here have found something that works for them. They know how exercise and diet are interwoven for them. Won't work for everyone.

3 of my family are very slim. One of them has a diet and exercise lifestyle that would suggest they should be overweight but they are underweight. I often say scientists should study them and see why and how. And no they won't change as they get older. Their grandad was the same.

OP is right that (weirdly) the general consensus from the science community in recent years is that exercise does not play a significant part in weight loss.

like other people on this thread, that consensus (by the way OP - does not make it ‘a scientific fact’) feels anecdotally wrong to me. I lost weight at times in my life when I increased activity levels (& I’d go so far to say I ate more…marathon running), just as others are saying.

scientific consensus does evolve (especially when it relates to diet and nutrition) over time, and I really expect this to change as well. That said, it seems to be the case that if you take a group of heavily overweight people - getting them to exercise every day is not going to by itself bring them to a healthy weight.

regardless, as others have said: exercise is really good for you, whether or not you lost weight! So do it (whatever you find that works for your body).

I haven't RTFT but from that comment I don't see any misunderstanding of BMR. You are of course correct in that exercise is not part of BMR but the OP's point is that your BMR is not constant and unchanging (for most of us anyway). If you exercise more your body may well burn more calories for the hour or so that you're doing it but when you go back to resting, your BMR will slow down so that the by the end of the day no extra calories have been burnt.

So if you run a marathon and burn several thousand calories, that means your BMR (which for most people is somewhere below 2000 calories a day) drops to below 0, and all the rest of the time your body is actually GAINING energy rather than using it in performing its vital functions! Right?