On Monday, a friend sent me this link to an article about the role of exercise is weight loss. Basically, the article says it doesn’t work. I agree. I’m sure it may work for the odd individual, but overall, it’s a pretty hopeless. I mentioned this to a patient yesterday who was seeking to shed some unwanted pounds. His reply was that while he was surprised that such a common notion (exercises helps weight loss) is wrong, it utterly mirrors his experience in real life ” it doesn’t matter how much he exercises, his weight stays stubbornly the same.
Before we look at the evidence, let’s challenge the notion that exercise speeds weight loss from a theoretical perspective. While exercise burns more calories than sitting or sleeping, it doesn’t burn that many. A 30-minute jog will burn about 290 calories. However, just sitting watching television will burn about 40 calories in the same time, so the additional calorie burn for half and hour’s worth of jogging is 250 calories. Imagine doing this 5 times a week. The total calorie burn from exercise for the week comes out at 1250 calories (250 x 5). Now assuming that all of those calories will be lost in the form of fat, and that we don’t eat a bit more as a result of expending more energy (more on that in a moment), then the amount of fat lost over the week from our jogging endeavours is about 140 g (less than a third of a pound). Not exactly dramatic, is it?
The other problem with exercise is that people who exercise more tend to be hungrier and eat more too [1]. To undo the calorie deficit induced by a 30-minute jog doesn’t take much, either (3 plain digestive biscuits will do it).
The fact that exercise does not burn that many calories and often causes increased food consumption could make getting into significant calorie deficit through exercise nigh impossible.
So, what does the science show regarding exercise and weight loss? The most comprehensive assessment of the impact of exercise on weight loss to date was conducted by members of an international group of independent researchers known as the Cochrane Collaboration. The review included 43 individual studies, and its point was to quantify the effect that exercise has on weight loss [2]. The amount of exercise prescribed in these studies varied from study to study. Typically, exercise sessions lasted 45 minutes with a frequency of 3-5 times a week. Total length of the studies ranged between 3 and 12 months.
The individual studies in this review were designed to study different things. For instance, some of them compared the impact exercise or diet has on weight loss. Here, the results showed that the ‘dieters’ lost between 2.8 kg and 13.6 kg in weight. On the other hand, exercisers lost between just 0.5 and 4.0 kg in weight.
Some other studies in this review compared the effect of diet and exercise with diet alone. Here, it was found that weight loss for those dieting and exercising was between 3.4 and 17.7 kg, but for those just dieting was 2.3 ” 16.7 kg.
Overall, the additional weight loss from exercise averaged out at a shade over 1 kg.
For example, imagine sorting out your diet and in 6 months you find you’ve lost 10 kg in weight. If, on top of this, you had been exercising, say, for 45 mins, 4 times a week, you could expect to have lost about 11 kg. And the time you would have spent exercising to get this additional 1 kg weight loss benefit? – 69 hours (!)
There are plenty of good reasons for taking regular exercise. Weight loss isn’t one of them.
References:
1. Finlayson G, et al. Acute compensatory eating following exercise is associated with implicit hedonic wanting for food. Physiol Behav. 2009 Apr 20;97(1):62-7
2. Shaw K, et al. Exercise for overweight or obesity. Cochrane Database of Systematic Reviews 2006, Issue 4. Art. No.: CD003817. DOI:10.1002/14651858.CD003817.pub3
Whilst this is true, diet is certainly the key factor in weight loss, for a healthy lifestyle some form of exercise is necessary, to maintain and create muscle mass, improve body composition, stimulate immune respons eand stress relief.
Good post John, and in the main I am with you that exercise has limited applications for weight-loss.
In the natural world animals have to live within the constraints of the natural food or subsistence economy. This is not an economy involving money but an economy involving calories and nutrients. Creatures must provision enough food to meet their energy requirements to exist, avoid predation, find shelter, and produce progeny. This imperative is so crucial that there is a word for those that fail to satisfy the requirement – EXTINCT. Animals generally show an economy effort in the way they live. Unnecessary activity is wasteful of energy. Humans who live subsistence lifestyles show the same strategy.
It is the breakaway from the subsistence economy and the ability to exceed that which facilitates modern civilisation and industriousness. It explains our ability to migrate out of habitat and proliferate. The idea is worth sleeping on – it reveals a lot; rather contemplation of the contrasts between then and now reveals a lot. There does not seem to be an evolutionary imperative that exercise is essential and on the basis of this I’d be very supportive.
However, what of the effect of increased and consistent activity levels upon basal metabolic rate and what of the distinction of exercise as applied to good or poor dietary habits?
Also, what of the role of musculature in insulin regulation and energy(glucose) management?
As a type 2 diabetic I have come to appreciate the role of the liver and muscles in ‘sinking’, or buffering energy as glycogen. Might part of the problem for insulin resistant and type 2 diabetics be a reduction in the capacity to re-release glycogen from the muscles thus denying future buffering of glycogen?
I have found exercise highly effective in aiding release of glycogen. On a poorly managed dietary regime I feel noticeably leaden in the major muscle groups. Exercise is important to me in removing that leaden feeling and delays its’ return.
I acknowledge people may differ, but my personal experience suggests that the muscles are important in the flow and management of energy around the body and consequentially I might think it reasonable to consider whether inadequate levels of activity, in tandem with reliance upon high GL carbs and fructose, might contribute to progressive metabolic dysfunction, weight gain, IR and T2db. ..?
John,
I am inclined to agree with the overall tenet of this post, but with one or two caveats.
Broadly this echoes my own experience. I exercise about 10 hours a week, maybe alittle more, and this has made next to no difference to my weight.
However I do think that more intense exercise, such as interval training, sprinting and lifting heavy weights may be more beneficial – perhaps by the indirect route of improving insulin sensitivity, fat metabolism, and reducing appetite. One problemn with this approach is that you need a good base level of fitness to actually run,cycle or swim fast and to lift heavy weights. Perhaps hill walking is a good introduction for some.
I sometimes wonder if, as we get older, we think to much about the science of exericse and over complicate things. When you are young there is a tendancy to do things as quickly as possible; you tend to run everywhere as fast as you can, and then to relax once you are tired. I can’t imagine a child volantarily jogging, or doing a slow steady cycle or swim.
From what I have picked up, long duration aerobic exercise is strssful to the body: it weakens the immune system and results in the release of stress hormones such as cortisol, which actually impede weight loss. This, in combination with the generally favoured low fat high carb diet is very unlikely to lead to sustained weight loss and good health for those seeking to improve their health through weight loss.
Better in my opinion to do what comes naturally and exericse in short intense bursts, be generally active, and eat natural unprocessed foods (easier said than done).
Also, I think, its worth considering the fact that for many the journey to being overweight is a long one: probably the consequence of years on a poor diet and minimal exercise. Its quite possible that turning that around will also be a relatively slow process. Maybe there might be some initial quick weight loss, but to get to a ideal weight it may take several years, if not longer.
Some suggestions worth trying are:
(i) Try to run a 6 minute mile (as a target)
(ii) Lift in excess of your own body weight.
(iii) Do 40 full press ups, or more.
(iv) Sprint – run, swim,cycle as fast as you can for maybe 20 seconds, rest 20 seconds and repeat 5 or 6 times.
There has been some reseacrh tp show that high intensity interval training improves insulin sensitivity and actually improves stamina as well. I believe this is an approach worth following for those who are dissappointed with their return from their exericse regime.
I tend to follow the rule that if something continues to yield disappointing results, its well worth trying something else in search of a better outcome.
Paul Anderson.
Exercise may not make you lighter but it can certainly change your figure!
I’m wondering what the aim of your article is, Dr Briffa? You explain your meaning quite clearly and technically, but don’t mention, as Chris points out, the effect of exercise basal metabolic rate, body composition or indeed the fact that most people want to lose weight in order to change their shape.
I see exercise as an important part of a a healthy regime (which, of course, has many more considerations than simply shedding the pounds). I hope that this article won’t erode too many people’s motivation to keep moving.
Jenny
As an exercise physiologist/nutritionist who has spent the last 15 years working in the fitness industry (mainly as a Personal Trainer), I agree with the above to a point. When you look at individuals who may need to lose 20-40kg of body fat & then compare many of the so called best diet &/or exercise plans, most are likely (if compliance is high) to lead to a 5-10% reduction in body fat in a 1-2 year period. So once over a certain threshold of obesity/metabolic damage, options start running out pretty quick. That’s why, as I read the evidence, I think past a certain waist threshold, there isn’t much that can be done.
Specifically comparing exercise with diet; very very few of the studies calorie match the diet & exercise groups. That is, if a diet is structured to induce a 3500 calorie deficit per week & the exercise programme only induces a 1500 calorie deficit per week, is it any wonder the diet looks superior? If sufficient exercise was done to match the 3500 calorie deficit of the diet (and that’s a lot of exercise), then you would see little difference between the two groups. Apples aren’t being compared with apples in many of these study designs.
Mmm well in the story ‘ “I see this anecdotally amongst, like, my wife’s friends,” he says. “They’re like, ‘Ah, I’m running an hour a day, and I’m not losing any weight.'” He asks them, “What are you doing after you run?” It turns out one group of friends was stopping at Starbucks for muffins afterward. ‘ So apart from the fact that people who excercise get more hungry (off course they do) diet is a key factor. Since excercise has lots more benefits than losing weight ( if done correct) i’d say keep on excercising adjust your diet and you will shed extra pounds. Whoever said half an hour of running? Why not row or swim that burns a lot more and if you don’t eat/drink crap you can be thin as a whistle if you want. I really don’t see the point of your negative attitude you can easily turn it around. (Ever seen a fat guy/girl do the Tour de France? )
I certainly agree with Dr. Briffa’s conclusions. And this is why.
In Jan. 09, after a bout with a candida yeast infection, I put myself on a very low-carb, high protein and high fat diet. My choice of excercise is walking which is perfect for my age (72) once or twice a week for half an hour or so. By June 09, I had lost 10 pounds and I continue to lose weight slowly. I have a nice waist line and flat tummy. Although my yeast infection is long gone, I am continuing this sensible diet and like it. I feel more energetic, lighter and mentally sharper. My cholesterol has gone from 267 to 207 without statins. Just about perfect although I have read a lot about cholesterol being good for people my age as it is one of the main components of one’s brain and muscles and depressing it artificially can cause memory loss and muscle pain (heart is a muscle, right?).
One thing that the excercise advocates do not mention is the number of injuries excercise fans incur into, like tendon, muscle, knee, back injuries. Just take a trip to an orthopedic doctor’s office and you will find out.
Thank you for allowing me to put my two cents into this discussion.
To Ed, It is just not the case that you can be ‘as thin as a whistle if you ‘ I wont repeat the rest. As A nutritionist I have seen very many people who eat well and lose very little weight. At least Dr Briffa provides evidence. Where is yours ?
Tom Venuto has written an excellent rebuttal to the Time Magazine article:
http://www.burnthefatblog.com/archives/2009/08/why_time_magazine_owes_the_fit.php
On the other hand, it must be said that NOT exercising is most certainly likely to result in weight-gain, and also leads to over-eating etc etc
There are certainly many cases in free-living individuals where they either exericse at such a bovine speed that they may as well be on the couch for what they are likely to burn, or they over-reward their virtue in the gym with a muffin & latte from the gym cafe on the way out. 100cal burned, 250cal back in!
I think a distinction needs to be made between those who are normal weight & perhaps just a bit chubby, but otherwise have no metabolic dysfunction, and those who are anything from normal weight through to super-obese but do have some sort of metabolic dysfunction such as insulin resistance. The former are far more likley to be exercise-responders in terms of shedding body fat than the latter group.
I totally agree that exercise does not aid weight loss. In my own personal experience and that of my husband, with exercise, we both put on weight BUT approaching our 60’s, exercise is vitally important to both of us for how we feel about ourselves and how we look. A firmer, more muscular body as we age as opposed to everything going a little south makes us feel and look better. Then – what do we mean by exercise? For me it is dancing for him bike riding and golf. I think it is a whole package – concentrating on ‘weight loss’ for some ends up with weight gain. Doing exercise you enjoy usually means raised levels of feel good endorphins – an improvement in muscle to fat ratio (especially as we age) and for most people an urge to eat better – less processed – more fresh foods to enhance the feelings of well being.
BMI does not take muscle weight into consideration. If you gain muscle, your metabolism increases. If you strengthen your heart, you will live longer.
added sugars are teh cause of weight gain in this country and the cause of failure for lo carb diets. Sweeteners and “sugar-free” foods with dextrose and polydextrose keep insulin levels high. I watch people put 5 packs of equal in a large cup of cofffee, so I would also say it is addictive, just a guess.
This is disappointing John to hear you put down exercise in regard to weight loss.
Sure you example/reaserch you gave in my experience both in the trenches & continual education in the fitness industry, is “correct”!
But, people aren’t going to take what you say in this post with a grain of salt and think,
“oh it’s because aerobic conditioning, is not ideal for weight loss, so does that mean resistance training will yield different results compared to aerobic training?”
They are going to think, exercise sucks so why do it for weight loss!!
There is a time & place for EVERYTHING,
You are correct, exercise doesn’t aid weight loss. But it sure as hell helps when it comes to body composition.
Of course…walking isn’t exercise. Neither is a bunch of things people want to call exercise. Moving isn’t exercise. Doing a bunch of low intensity yoga classes isn’t exercise either. Exercise needs to kick the crap out of you because exercise is supposed to make you BETTER than you were before.
So for all the skinny idiots who are eating well who don’t exercise, guess what, you can go on being able to do nothing other than blogging about how your diet works.
I’d rather be able to do just about any physical task out there and do it well. Functionality trumps inability any day.
Anectodal evidence through people saying “I did this” isn’t scientific. In fact its horrid. You go find me a bunch of people who do high intensity exercise and I’ll show you non-fat people. You show me a bunch of walkers in the mall, and the majority of them still cling to extra pounds no matter how well they eat.
Normal is not slightly overweight, overweight is overweight no matter how slightly it is.
So do I disagree? Yes. People who do real exercise aren’t fat. Weight is a measure of gravity. Fitness and health are completely different and a real study will show that fit and healthy people ALWAYS exercise.
I agree that weight loss, as a general term, won’t be achieved by exercise only. Exercising do however bring about a big difference in body composition, which means that more centimeters will be lost when combining certain exercises with the right diet.
If we are going to talk anecdotes then I can add my own. I have spent two months on two different diets and exercised throughout. Yes – the sort of exercise which kicks the crap out of me. Running hills, sprints and intervals for 30-60 mins. Plus aerobics and general daily walking. I am 2 stone overweight and this is not at all an easy route for me.
Month one low fat/calorie diet – counted everything and did the above exercise. Lost 3 pounds…. but lost 3% body fat
Month two tried high protein low carb same exercise – lost 7 pounds and another 2% body fat.
It is clear what worked for me. the change in weight loss must have been down to the diet – but my improved metabolism must have also had the effect of making the weight loss easier.
I have always exercised to one degree or another and alway found it easy to put on weight. Doesn’t mean i will stop though!
Dr Briffa:
“There are plenty of good reasons for taking regular exercise. Weight loss isn’t one of them.”
Yes, yes we know exercise has benefits but for fat loss look to your diet.
Venuto blames it on lack of willpower, no self control:
“That doesn’t mean exercise is ineffective for weight loss, it means you need DIETARY RESTRAINT to lose weight! Dietary restraint means that if you want to lose weight, sometimes you have to feel hungry and NOT EAT! (even while stressed, emotional, tempted, etc.)”
You don’t have to be hungry to lose weight.
Disappointed with this blog post. I was under the impression that Dr Briffa often took a more holistic approach to health issues, and this post seems one-dimensional in the extreme, and lazy to boot. In fact it sounds like a personal justification for avoiding exercise. Perhaps the “science” is correct, but the toss-away line that there are “plenty of good reasons to exercise but weight loss isn’t one of them” is shallow and dismissive. I’m sure there are many people who exercise without any weight loss, or who blow the calorie deficit immediately afterwards etc, but there are many others who find exercise a huge help during attempts to lose weight. For me, along with noticeably improved muscle definition and fitness, the sense of improved well-being and greater awareness of my body that comes from exercise is inextricably linked to my motivation to stick to a healthy eating plan. Yes, I can lose (post-pregnancy) weight through diet alone, but I am much more successful when I exercise as well because I feel healthier and more energetic all round, and I am less inclined to reach for stodgy foods. This in itself is a simplistic account of the relationship between diet and exercise for me, but I’m sure you get the general point. Ignoring this psychosomatic – or whatever it might be termed – impact of exercise is a careless omission, and a surprising one from Dr. Briffa.
Verity, you’re over-reacting.
As Dr Briffa said there are benefits of exercising – plenty benefits. But if you are exercising and not losing weight take a look at your diet. End of story!
Sue
“You don’t have to be hungry to lose weight.”
Couldn’t agree more.
Look Hilda, i move a lot i eat a lot. I don’t move i get fat, simple as that. And if people ‘need’ to reward themselves after having done some excercise, well….. And yes you don’t have to be hungry to be thin. Funny thing to try when you’re hungry get of your but, the hunger will disappear. Not moving and eating will in the end make you weightier than eating and moving if you eat normal food (ie. no donuts and other non nutritious stuff)
Hi Ed, I don’t know why you addressed your comments to me. THey do not seem to be in line with what I said. Maybe you got the name wrong. However now that I have have begun I will say that weight gain is a very complex matter . We assume that it is always a bad thing but polar bears don’t do so badly. It is also genetic and is affected by such things as candida, thyroid, conversion of T4 to T3 and T2, viability of thyroid receptor sites, food intolerance, pollution, size and function of liver, amount of muscle mass, amount of brown fat, nutritional deficiences which affect the production of energy in cell. Of course if you starve you will lose weight but you will also become ill. .
Great blog. I think Dr Briffa should be congratulated on creating a forum where so many diverse views can be aired/shared. I am fascinated by the anecdotal v scientific evidence debate. This is a blog not a scientific paper and surely there is room for both and both will add value? With science it can be argued ‘who vets the vet?’ There is good and bad and it changes and reflects the knowledge as it stands in a period of time. As regards exercise I have an original Dr Atkins 1937 diet book that exhorts you not to exercise as it will just make you hungrier (hmm – what goes around, comes around) Exercise for purposes of losing weight
would appear to have occurred in the 1950’s, 60’s . A useful article is http://www.guardian.co.uk/lifeandstyle/2007/oct28/ by Gary Taubes. So, there is some science, what about anecdotal – another way of putting it would be perhaps ‘to ask the crowd’. Putting together people’s actual experiences and being able to learn from them,if we can be unbiased enough to listen, often is valuable. As regards eating for health (and possible weight management) one of our problems is that we no longer pass on cultural knowledge. In the words of Michael Pollen, in his book ‘In Defense of Food’ “Most of us no longer eat what our mothers ate as children or, for that matter, what our mothers fed us as children. This is, historically speaking, an unusual state of affairs”. My parents lived through the war and rationing. They grew and dug veggies in their back garden and did not have a car and used their bicycles. They had enough food but not an abundance and sugar was rationed. I have pictures of them – they look skinny.
Whoops – before anybody pulls me up (who vets the vet indeed) I meant the original 1937 book of Food Combining by Dr William Howard Hay – not Dr Atkins!
I was also disappointed in this blog but having a lot of respect for Dr Briffa was prepared to take it seriously.
I exercise regularly and lately for many reasons have not been able to (and have put on weight). Over the past 10 days since reading this entry I’ve been exercising again and have been noting the differences between when I do and when I don’t. In my case I eat less when I exercise, not more. Perhaps this is because I have PCOS and am insulin resistant. The days when I exercise (in the morning) I have no discernable blood sugar fluctuations, eat because of biological hunger and stop when I have had enough. The days when I don’t exercise I am much more likely to eat because of other reasons – i.e. boredom and much less likely to feel when my body has had enough and just eat for the sake of eating.
Another thing I often find is that I may come home from work hungry and craving allsorts of foods (often unhealthy) but after I have practised yoga, something I often do in the evening my ‘hunger’ has considerably decreased.
So for me exercise is an essential part of weight management, even if this is only because it prevents me from overeating.
I looked at Dr Lustig’s video recommended by Anna Salvesen in a comment relating to American Heart Association article. Was interested in a slide on:
Why is exercise important in obesity?
Not because of calorie reduction but:
1. improves skeletal muscle insulin sensitivity (reducing insulin levels)
2. reduces stress and cortisol release, thereby reducing appetite
3. makes the TCA cycle run faster, detoxifies fructose improving hepatic insulin sensitivity (he explains in video disastrous biochemical effects of fructose)
So maybe there is a role for exercise?
Seems to echo some of the personal experiences in comments above…
The rest of the video is a plea to avoid fructose and sucrose, in all sugared drinks including fruit juice and alcohol, eating carbs only in their natural state ie. with fibre, waiting 20 minutes before having a second portion (one could also say relax as you eat, mindful eating).
Link was http://www.youtube.com/watch?v=dBnniua6-oM
Dr Briffa
Why have you selectively quoted Cochrane?
As Ben Goldacre writes:
“The Cochrane Library is a non-profit collaboration of academics who produce unbiased, systematic reviews of the medical literature, and they have a systematic review of all the 43 trials that have been done on exercise for weight loss. This produces clear evidence that exercise is beneficial, albeit more modestly than you’d hope. “Exercise plus diet” was compared with “diet alone” in 14 trials : both groups lost weight, but 1.1 kg more in the exercise group. High intensity exercise was compared with low intensity in 4 trials, high intensity exercise came out better in all of them, with extra weight loss of 1.5 kg. There are also improvements in blood pressure, cholesterol, blood sugars, sense of well-being, and so on.”
Exercising to “burn” calories is a futile waste of effort, but increasing activity, as opposed to that fearsome word “exercising”, to keep the body in good working order, regardless of fat, is just good sense.
An appropriate phrase, with regard to mobility and lean mass, is “use it or loose it”.
I have to disagree with you on this one. I for one have eaten very healthy my whole life, and ended up putting on a lot of weight when I had my son. And by a lot, I mean about 55 kg (and I was tiny before, I put on more than twice my weight). There was nothing that I could do about my diet, it was already very good. So, I started exercising. And in the past 18 months, I’ve lost 45 kg, and I’m smaller than I was before because I’ve toned up big time. I think exercise is very important, and although people may not have ‘lost’ as much weight, there is no information saying that they have changed their body shape with exercise, ie. more muscle, less fat.
There’s exercise and there’s exercise. As a genetic throwback I’m with Mark “Primal” Sisson: move slowly a lot, run very fast occasionally, lift heavy things. That has the most bang for the buck for *my* body.
My cousin just came to visit. He ran round the village first thing in the morning – then shovelled a whole bowl of cornflakes and skimmed milk into his face. This is where the current recommendations for high cardio fall down IMO, if you use the exercise purely to overcome the effects of overcarbing, and do so much that you need to top up with carbs again straight afterwards it’s probably not going to help much compared to adding relevant exercise to an anatomically correct diet. Hence probably the variations from different studies.
I can’t believe a third of a pound weight loss through the effects of exercise alone is so easily dismissed: “not exactly dramatic is it”. This equates to over 17 pounds a year – which is EXACTLY dramatic – FACT.
Combine that with a sensible daily calorie deficit and the body of your dreams is very achievable… willpower willing !
I think Dr. Briffa’s books are off my reading list from now on if this is representative of the quality of the material contained in his literature.
Is there a study that monitered the caloric burn post-exercise? We know that the calories burn during low-intensity exercise doesn’t equate to a lot. But the bonus round is the caloric burn after en intense session and its influence on the metabolic rate. If you are going to engage in an exercise program to lose fat, maximize your time.
My personal experience:
I took up jogging and cycling in order to lose weight. My CV fitness impoved – I could jog and cycle further and faster – but my weight did not change. However, my knee started to hurt. I stopped.
A few years later I went on Atkins to lose weight. My weight reduced steadily and it was no hardship to eat low carb. When I had lost 15 lbs I felt so good I started to take exercise, this time in the gym with the emphasis on weights and stretching rather than pounding the treadmill.
My experience tells me Dr B has it exactly right – when I wanted to lose weight, it was not exercise but diet that actually worked. Now my weight is under control I want to improve my stength, speed, stamina, etc – for which I take exercise.
It’s not the calories you burn during exercise that are important. If you exercise aerobically and consistently, it raises your Base Metabolic Rate, basically the amount of calories you lose while doing nothing. If you exercise 3-5 times a week, you’ll eventually lose weight while you’re asleep. (as long as you keep doing it!)
I’m intending of starting an exercise routine very soon. I eat a lot and i take a lot of sugared drinks. My stomach is getting bigger and i feel nervous or maybe anxiety almost everytime. My weight now is 108 kg. My dream weighp is 75 kg. I’m 6ft. I want to know which works faster? The dietary routine or exercise, or could it be both?
Gracias for exalting me to go do my own my own research.
Yours was way more thought out than mine.