Exercise for weight loss – a myth?
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Exercise for weight loss – a myth?
Since 1980 obesity has doubled worldwide, with about 13% of the global population now registering as obese, according to the World Health Organization (WHO).
It is estimated that being overweight or obese is responsible for 5% of global mortality, and physical inactivity is rising.[1] In addition, being overweight is a contributing factor in non-communicable diseases, such as heart disease, diabetes and cancer, and these have all risen exponentially over the last 20-30 years.
It is true that our lifestyles have become more sedentary. In my grandparents’ day, for example, cars were seldom used; they walked a lot more than we tend to do today. There were few lifts (elevators) and less public transport. In my own generation, we all walked or cycled to school and we played outside after school and on the weekends – we didn’t have computers or mobile phones or even TV (until later on). Today the landscape has changed and many are concerned about the amount of ‘screen time’ children have compared to playing outside . . . and we see this in adults too.
Is there a correlation between the two, i.e. is lack of exercise causing, or contributing to, the rise in obesity?
It has been shown that physical activity is a key determinant of energy expenditure and thus is fundamental to energy balance and weight control.[2] So it can be easy to postulate that exercise is the panacea for losing weight that many think it is. Indeed, some fitness publications and some gyms suggest exercise is far more important than diet for weight loss. However, recent research has stated that exercise accounts for only about 10% of weight loss.[3]
Benefits of exercise: Exercise as Medicine[3]
| Health Condition | % reduction in developing the condition by doing recommended amount of exercise (30 mins x 5 times per week) |
|---|---|
| All cause mortality | 30% |
| Heart Disease | 20 – 50% |
| Hypertension | 52% |
| Stroke | 20 – 40% |
| Type 2 Diabetes | 30 – 50% |
| Obesity | 10% |
| Cancer | Unclear |
| Breast cancer | 20 – 30% |
| Bowel cancer | 30 – 50% |
| Depression | 20 – 33% |
| Dementia | 20 – 50% |
| Low back pain | 40% |
| Osteoarthritis | 22 – 83% |
| Falls in the elderly | 30 – 50% |
| Osteoporosis | 40% |
| Major fracture | 35 – 65% |
I love this piece of wisdom I found in the BMJ journal:[4]
You cannot outrun a bad diet
One very under-appreciated fact about exercise is that even when you work out, the extra calories you burn only account for a small part of your total energy expenditure (calories burned every day).
Obesity researcher and neuroscientist Alexxai Kravitz[5] explains that there are three main components to energy expenditure:
- Basal metabolic rate, or the energy used for basic functioning when the body is at rest
- The energy used to break down food
- The energy used in physical activity
He says that it’s generally accepted that for most people the basal metabolic rate (which we have little control over) accounts for 60 to 80 percent of total energy expenditure, and digesting food accounts for about 10 percent.
“The implication here is that while your food intake accounts for 100 percent of the energy that goes into your body, exercise only burns off less than 10 to 30 percent of it.”[6]
Given this statistic, we could ask: how important is exercise for losing weight?
There have been recent studies on the issue of exercise for weight loss:
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One study found that total energy expenditure eventually plateaus – so exercising for longer may not help, as the body sets limits to how much energy to expend.[7]
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Another study by anthropologist Herman Pontzer[8] on a hunter-gatherer tribe in Tanzania (the Hadza) found that, although they were physically very active and lean, they burned the same number of calories every day (through movement and the energy used to run the body's many functions) as the average American or European, even allowing for body size! Their conclusion: the Hadza do not overeat, so they are not obese. The science of energy expenditure is still evolving, however, this study is very significant in the context of the global obesity epidemic.
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A recent Cochran Review[9] of exercise studies found that physical activity alone led to only modest weight loss: "When compared with no treatment, exercise resulted in small weight losses across studies."
In my experience, both as a person who has exercised excessively in the past, and someone who has taught exercise for twenty years, the answer seems to me to depend on how much exercise you do. For example, when I exercised excessively: 11 yoga classes a week, 2-3 aqua aerobic classes a week, cycling 7-10 hours a week, and in some years also squash 4-5 times a week, gym 5 days a week (aerobic classes plus weights plus cardio workouts), swimming 3-4 hours a week, as well as the odd game of tennis, kayaking and skiing – I could eat and drink whatever I liked, including large amounts of chocolate, cakes and fruit juice.
However, this amount of exercise takes a lot of time, willpower and effort and has a huge toll on the body, so most people would not exercise to this extreme. When I stopped doing so much exercise, when I came to understand and feel how harmful it was for my body (although I still exercised as a part of my healthy lifestyle, how I exercised changed), I still ate the same quantities of food (well, perhaps a little less as I no longer stuffed myself with bread and buns following a long cycle ride or a long swim) . . . and I started to put on weight.
If losing weight through exercise alone can only be done by exercising excessively, what effect would this have on our overall health, especially for our musculoskeletal body?
I know for me that when I exercised to extremes I was constantly being injured and was constantly exhausted (and overate to counteract that exhaustion), and now later in life I have joint issues, especially with my hips and knees.
How often do we hear of similar stories in our professional athletes, even at young ages? A friend who is a naturopath said she sees many fit-looking people who are actually falling apart, with a lot of inflammation in the body and fatigue.
So it could be argued that excessive exercise is just as damaging to our overall health as too little exercise, especially for our musculoskeletal body, but also for our nervous system (we end up pushing ourselves beyond our safe limits, which could lead to exhaustion and depression) and vascular system (I have often heard of older men suffering heart attacks on the squash court for example).
Also, when I went for a long bike ride, or skied all day, or went for a long ocean swim, I was usually ravenous afterwards and ate a lot, especially carbohydrates, as these were promoted then (by sports nutritionists) to assist with recovery (many now advocate high-fat diets instead). This counteracted the exercise – in fact, one slice of pizza, or a latte, can undo the benefits of one hour of exercise! Sometimes I did not feel like eating but I was so exhausted that I had to eat so I had the energy to carry on with my day. I also often had to lie down for a long rest after exercising to extreme. How I was exercising controlled my whole lifestyle. In fact, all I was doing was working, eating and sleeping to exercise. I ran myself into the ground.
Many sports nutritionists still advocate eating carbohydrates immediately after exercising to extreme – I remember being horrified to discover that students rowing in school competitions are given 'jelly babies' (soft sweets) between and after races by their parents and or coaches, on the advice of their coach or nutritionist.
The WHO recommends 150 minutes of moderate intensity exercise a week for adults aged 18 or older and at least 60 minutes of moderate to vigorous exercise a day for 5-17 year olds.[10] The WHO recommendations focus on exercise for overall health and particularly to prevent non-communicable diseases and their risk factors, such as raised blood pressure and blood sugar and being overweight.
– Children and youth aged 5-17 should accumulate at least 60 minutes of moderate to vigorous intensity physical activity daily.
– Amounts of physical activity greater than 60 minutes provide additional health benefits.
– Most of the daily physical activity should be aerobic. Vigorous intensity activities should be incorporated, including those that strengthen muscle and bone, at least 3 times per week.
– Adults aged 18 years and upwards should do at least 150 minutes of moderate intensity aerobic physical activity throughout the week or do at least 75 minutes of vigorous intensity aerobic physical activity throughout the week or an equivalent combination of moderate and vigorous intensity activity.
– Aerobic activity should be performed in bouts of at least 10 minutes duration.
– For additional health benefits, adults should increase their moderate intensity aerobic physical activity to 300 minutes per week, or engage in 150 minutes of vigorous intensity aerobic physical activity per week, or an equivalent combination of moderate and vigorous intensity activity.
– Muscle strengthening activities should be done involving major muscle groups on 2 or more days a week.
– Adults aged 65 years and above, with poor mobility, should perform physical activity to enhance balance and prevent falls on 3 or more days per week.
– When adults aged 65 and above cannot do the recommended amounts of physical activity due to health conditions, they should be as physically active as their abilities and conditions allow.
In my experience this moderate amount of exercise, whilst sufficient for overall health and wellbeing, and perhaps for small changes in weight, would not be enough on its own (i.e. without dietary factors) to lose much weight, unless of course you were not exercising at all when you started an exercise programme – which would account for the 10% perhaps. However, I have found that moderate exercise can certainly help you maintain your weight, if combined with watching what you eat.
Dieting to extreme and losing weight quickly has been found to be ineffective because your metabolism slows down (like a 'survivor mechanism') – conserving energy to try to store fat for future energy needs.[11]
What is the answer then to the issue of exercise and weight loss?
My experience, both with my own exercise regime and with supporting people over many years with their exercise programmes and goals, has led to the following understandings:
– Exercising moderately 30-45 minutes every day is the most effective way to exercise to maintain body weight and overall health and wellbeing, with daily walks being especially effective (for both cardiovascular and musculoskeletal benefits, as well as mental health benefits), together with increasing 'incremental exercise', such as taking the stairs instead of the lift and walking to your local shop instead of driving. If you are too overweight to safely walk, you could swim or aqua jog in a deep water pool or the sea. I have found that such consistent, moderate exercise has greatly supported me to maintain a healthy weight, without the harmful effects of excessive exercise that I used to experience. If you have never exercised, or have not exercised for a long time, this consistent moderate exercise could also lead to gradual (and therefore safe) weight loss, assisting as it does with balancing energy, with your weight balancing out over time.
– It is very important to first, choose exercise you will enjoy, and second to exercise at an intensity you can comfortably handle, gradually increasing the intensity when your fitness improves. Exercising in this way is much more likely to support your whole body – not just your mind – i.e. you will exercise in a way that you choose to, rather than doing what you 'think' you should be doing or what someone else tells you to do, or what others are doing (and you trying to compete with them).
– When you exercise in 'conscious presence' i.e. with your thoughts on whatever your body is doing, it supports you both to enjoy your exercise and to stay aware of what your body is telling you, which means you are much less likely to override your body's messages (which are constantly being given to you) and exercise excessively or in a way that ultimately can damage your body. Of course it goes without saying that you cannot do this if you are distracted by, for example, music (in your headphones) or drinking a cup of coffee (both of which I see a lot when I am out walking). As far as enjoying exercise is concerned, I find that if my thoughts wander away from what I am doing (which happens quite a lot!), I lose the enjoyment of simply being present with my body as I am exercising, so what I do then is feel my feet on the ground or my arms swinging (if walking) or my arms gliding through the water (if swimming). The feeling of my body exercising with such presence – in a way that supports my body – is a wonderful feeling as it is not often I allow myself to stop the constant thinking and simply focus on being me.
– When you let go any intentions or goals, such as exercising 'to lose weight' or 'get fit', which can cause a lot of stress, and exercise simply for the joy of being with your body, you may find (as I do) that, not only do you increase your fitness and lose or maintain your weight anyway, effortlessly so, but you love exercising and it becomes an important and really enjoyable part of your day.
– Don't use exercise as an excuse to eat more than usual.
– It is very difficult to lose weight by simply exercising more, unless perhaps you exercise to extreme, which has consequences for your musculoskeletal system and other systems in your body.
– Let your body guide you as to what exercise to do and for how long, as your body is very wise and is the greatest marker of what is true for you, a marker that says 'yes' or 'no'. With your body to guide you, it will find both its natural weight and a natural way to exercise that supports your whole body, including your mind.
The way we use our bodies is not true
There is a truer way to use our body which feels beautiful.
So, is exercise for weight loss a myth? Yes . . . and no.
Exercise, along with sensible food intake, can support you to lose a moderate amount of weight if you need to. It is very important for maintaining a healthy weight and for overall health and wellbeing (and feeling good about yourself) and especially reduces the risk of Type 2 diabetes, stroke and heart disease. It is not however the only answer for weight loss – how much and what we eat and drink is far more important.
It is clear that exercise alone cannot lead to weight loss, unless it is excessive physical activity, which could induce weight loss in some people. However, excessive exercise is not the best way to lose weight as it is not sustainable long-term and it can be very harmful to the body.
References:
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Weight-loss, Weight, Fitness, Diets, Healthy living
