When you examine the evidence relating to exercise and health or exercise and weight loss you quickly realize that in fact there is no evidence supporting the contention that exercise is in any way good for health or good for weight loss. The few studies that specifically examine the effects of exercise on weight loss are either confounded by human life-style factors or they fail to prove any direct link between exercise and any kind of lasting healthy weight loss.
If you are used to doing exercise on a regular basis, you may begin to feel depressed, exhausted, constipated, or irritable as a result of giving up exercise. This is temporary, akin to the withdrawal symptoms of giving up a drug. Exercise can be addictive, and this may apply to you. If so, you need to be firm and determined in giving up all forms of exercise. Once you overcome the initial shock to the system of giving up exercise, you will soon experience the exhilaration of better health and well-being in many ways.
As an aside, when you look at long-lived people, they invariably have a lifestyle of being active in their daily lives but without doing any kind of strenuous exercise. Long-lived people in the world often work in the outdoors but their activity is usually not strenuous enough to make them breathless and/or sweaty on a regular basis.
Is there any evidence that exercise helps lose surplus bodyweight or that it helps maintain a slim body? When studies relating to exercise and health (or exercise and bodyweight) are published, they are invariably misinterpreted and misreported because of the strong prejudice in favour exercise.
Indeed, few people have the knowledge or interest needed to interpret the scientific evidence and draw their own conclusions. In order to do this you would need to devote significant time and dedication to the subject (and an academic background would help). It is sad to see many health professionals parroting out-of-date and incorrect advice relating to health and exercise. Perhaps their busy lives prevent them from keeping up-to-date with new research or perhaps they're afraid that their credibility would be questioned if they change their life-long held beliefs.
Also, most so-called scientific studies do in fact lack scientific basis. And when they are published, they usually generate half-truths and faulty conclusions, and are cited out of context. Even highly rated studies published in peer-reviewed journals fall prey to misleading headlines in the press. Here are some examples of this:
Plosmedicine Study, 2012
News headlines: 'Exercise helps you live longer'
A study by Plosmedicine published in November 2012 concluded that "More leisure time physical activity was associated with longer life expectancy across a range of activity levels." This generated press headlines such as "EXERCISE INCREASES LIFE EXPECTANCY REGARDLESS OF YOUR WEIGHT." Source: Steven C. et al, Leisure Time Physical Activity of Moderate to Vigorous Intensity and Mortality: A Large Pooled Cohort Analysis, http://www.plosmedicine.org
When you examine the data in this study, you see that no distinction is made between (A) physical activity that does not make you breathless/sweaty and (B) exercise that does make you breathless/sweaty. So we don't know if greater life expectancy was gained from (A) or from (B) or some mix of the two.
Another weakness is that the study draws conclusions (about the number of longevity years gained from exercise) from lifestyle factors rather than from the exercise itself. In the study, it seems that lifestyle factors rather than exercise are what determine longevity:
"The association between physical activity and higher life expectancy was more robust among black individuals than among white individuals and among participants with some college or post-high-school training than among those with only a high school education or a college or graduate degree. Similarly, the association between physical activity and higher life expectancy was stronger among former smokers than among never smokers or current smokers, as well as among those with a history of cancer or heart disease than among those without such history. For the healthiest group—never smokers with no history of heart disease or cancer—a high physical activity level was associated with 2.8 more years of life expectancy."
Clearly, if you take a cohort of health-conscious people (including people who for instance give up smoking) and examine their levels of exercise, it is likely that such people will have a higher longevity compared to the population at large but not due to the exercise itself; rather, it is due to 'more healthy' lifestyle factors.
Another weakness of the Plosmedicine Study is that figures of longevity were based on averages rather than on specific individuals. It could be that individuals who did intense exercise in the study did not, in fact, gain a longer life. It could also be that individuals who avoided exercise and limited themselves to physical activity that did not make them breathless/sweaty did in fact gain a longer life. We simply don't know because average figures across the whole cohort were used when drawing conclusions about increased longevity.
Also, the data collected by the study was based on self-reporting rather than on objective scientific observation. Participants were asked to send in completed questionnaires about their lifestyle and degree of exercise. This method of scientific investigation is notoriously unreliable.
All in all, this study does not shed any light on the effects of exercise vis-a-vis longevity, and this is regrettable because it creates misleading headlines in the press that only serve to reinforce the myth that exercise is somehow beneficial.
Let's look at some other examples of misguided evidence and then in the next section we will see exactly why becoming breathless and/or sweaty is so bad for health and so counter-productive to losing weight.
University of Wyoming Study, 2012
News headlines: 'Regular Exercise May Help Fine-tune Appetite'
A 2012 study from the University of Wyoming looked at a group of women who either ran or walked and, on alternate days, sat quietly for an hour. [Source: D. Enette Larson-Meyer, et al, Influence of Running and Walking on Hormonal Regulators of Appetite in Women, J Obes. 2012; 2012: 730409]. The purpose of this study was to assess the effect of a 60-minute bout of exercise on circulating concentrations of ghrelin (a hormone that makes you hungry) and assess whether this affected appetite following exercise. Exercise was performed at a moderately hard intensity in two different modes: running and walking.
After the running, walking or sitting, researchers drew blood to test for the levels of certain hormones and then directed the women to a room with a buffet. Human appetite is complicated, driven by signals from the brain, gut, fat cells, glands, genes and psyche. But certain appetite-related hormones, in particular ghrelin, which stimulates hunger, are known to be instrumental in determining how much we consume.
Studies have shown that exercise typically increases the production of ghrelin. Workouts make you hungry. In the Wyoming study, when the women ran, their ghrelin levels spiked, which should have meant they would attack the buffet with gusto. But according to the Wyoming Study they didn’t. In fact, after running they consumed several hundred fewer calories than they burned. This prompted headlines such as 'The Appetite Workout' [New York Times] and 'Regular Exercise May Help Fine-tune Appetite' [runnersworld.com]. The accompanying articles reported or implied that exercise reduces appetite and hence helps you lose weight.
But in fact the Wyoming study readily admits that "from our study design it is impossible to determine whether our observed differences between running and walking are due to exercise or the physiological characteristics of the walkers who were on average fatter and less fit then the runners. Food intake following exercise in women are in agreement with previous studies in both sexes which found either no difference in food intake after a bout of exercise compared to a no-exercise control. We did not find significant differences in perceived hunger at any point following running or walking compared to rest, and small changes in hunger due to exercise may be difficult to detect using available methodology."
Watts Study, 2005.
News headlines: 'Exercise helps reduce body fat and protect the heart'
This study reviewed other studies and concluded that "These studies indicate that, although exercise training does not consistently decrease bodyweight or body mass index, it is associated with beneficial changes in fat and lean body mass. Exercise training improves cardiovascular fitness and muscular strength". [Source: Watts K, et al, Exercise training in obese children and adolescents: current concepts, Sports Med. 2005;35(5):375-92].
So this Watts study is saying that exercise does not reduce bodyweight or body mass, but that it does help to strengthen muscles and cardiovascular fitness. Clearly, exercise will strengthen muscles, but at a terrible cost. As you will see in this book, exercise causes a host of health problems. Muscles are best strengthened by doing physical activity that does not make you breathless/sweaty, such as walking, lifting and pulling activities.
As regards cardiovascular fitness, the Watts study in fact says that exercise improves 'endothelium function'. This refers to the flow of blood through the arteries. The reality is that the efficiency of endothelium function cannot be tested through exercise or by any other means. All that can be tested is endothelium disfunction. There is no known evidence to show that endothelium disfunction benefits from exercise. On the contrary, recent research is showing that exercise greatly accelerates the accumulation of plaque in arteries (see 'Why All Exercise is Bad For The Heart', DeliveredOnline.com).
Broom Study, 2009.
News headlines: 'Exercise prevents over-eating'
This study is often quoted by those who wish to argue that exercise suppresses appetite. [Source: Broom DR, et al, Influence of resistance and aerobic exercise on hunger, circulating levels of acylated ghrelin, and peptide YY in healthy males, Am J Physiol Regul Integr Comp Physiol. 2009 Jan; 296(1):R29-35]. The study concludes that "ghrelin (the hunger-causing hormone) may regulate appetite during and after exercise, but further research is required to establish whether exercise-induced changes in ghrelin influence subsequent food intake".
Exercise is known to play havoc with the body's hormones because of the stress that is put on the respiratory system, energy levels, and so on. This in turn affects appetite during and immediately after exercise (who wants to eat when you're exhausted and recovering from the exercise!). So although some research (such as the Broom Study) may show that appetite is suppressed during and immediately after exercise, there are no studies showing that appetite suppression has any lasting effect.
Indeed, anecdotal evidence clearly shows that later in the day the degree of hunger and food consumption is increased following a bout of exercise (and we all know this from personal experience). The drain on energy eventually compels the body to want to eat more to regain the lost energy. The Broom Study readily admits that it did not pursue the long-term effects of appetite suppression as a result of exercise by concluding "further research is required to establish whether exercise-induced changes in ghrelin influence subsequent food intake."
Lakka Study, 2005.
News headlines: 'Exercise fights obesity'
This study is a good example of research that reaches vague, generalized conclusions, without producing any clear specific evidence. The study concludes that "To combat the epidemic of overweight and to improve cardiovascular health at a population level, it is important to develop strategies to increase habitual physical activity and to prevent overweight and obesity in collaboration with communities, families, schools, work sites, health care professionals, media and policymakers". [Source: Lakka TA, et al, Physical activity, obesity and cardiovascular diseases, Handb Exp Pharmacol. 2005;(170):137-63].
Dangardt Study, 2013.
News headlines: 'Exercise reduces risk of early death'
The study concludes that "Exercise is associated with reduced long-term morbidity and mortality, but acute exercise can transiently increase the risk of fatal or nonfatal cardiovascular events. Low-intensity physical activity is important and beneficial to all individuals, including those with a high risk of adverse cardiovascular events. In individuals who are physically fit and who do not have genetic predisposition to, or signs of, cardiovascular disease, the greater the intensity and amount of exercise, the greater the health benefits". [Source: Dangardt FJ, et al, Exercise: friend or foe? Nat Rev Cardiol. 2013 Jun 25].
In saying that "Exercise is associated with reduced long-term morbidity and mortality" the Dangardt Study is unable to prove that exercise specifically reduces long-term morbidity and mortality. When you drill down into this and other similar studies you always find that the research is confounded by lifestyle factors. That is, people who exercise are more prone to follow healthy lifestyle factors such as not smoking, and following a healthy diet. It is very difficult to isolate exercise as such in any research and prove that exercise per se is responsible for better health, a longer life, a slimmer body or whatever.
The Maziekas Study, 2003.
News headlines: 'Exercise reduces child obesity'
This study specifically looked at whether exercise can help children lose surplus body fat, and unlike many other studies, followed up a year later to assess the long-term effect. [Source: M Maziekas, et al, Follow up exercise studies in paediatric obesity: implications for long term e ffectiveness,Br J Sports Med. 2003 October; 37(5): 425–429].
The study concluded that: "exercise is efficacious for reducing percentage body fat in obese children and adolescents, and exercise intervention may encourage long term maintenance of the observed gains."
But the Maziekas Study goes on to say that "The most significant limitation relates to the inability to control for numerous confounding variables during the one year follow up period—that is, dietary changes, illness, medication, etc." Clearly, when parents and their children become part of a health study (and knowing there will be a one year follow up), it is highly likely that this will influence behaviour in terms of diet and so on. Therefore, any conclusion that "exercise is efficacious for reducing percentage body fat" becomes highly suspect.
The Bostrom Study, 2012.
News headlines: 'Exercise combats obesity'
This is regarded as a landmark study because it is claimed that a new hormone was discovered called 'irisin'. The study stated: "We examined blood levels of irisin after exercise in mice and human subjects. Mice had significantly elevated concentrations of irisin after they were subjected to 3 weeks of free wheel running. Similar analysis in healthy adult humans subjected to endurance exercise for 10 weeks revealed a twofold increase in irisin compared to the non-exercised state. Exercise increases energy expenditure in mice and humans.... with no changes in movement or food intake. This results in improvements in obesity". Source: Pontus Bostrom, et al, A PGCI-a-dependent myokine that drives brown-fat-like development of white fat and thermogenesis, Jan. 2012 vol 281 Nature 463.
At the time that the Bostrom Study was published, it prompted press headlines around the world to the effect that exercise combats obesity by using up energy without making you eat more, but let's look at the facts.
It is well known to medical science that any kind of physical activity that moves the muscles will (over time) result in the muscles becoming firmer, thus increasing their capacity to store more energy. Flabby muscles mostly consist of white adipose tissue. Firm muscles mostly consist of brown adipose tissue. So the browner your muscle tissue the better. The Bostrom Study discovered that one of the hormones that helps to convert white tissue to brown tissue is the so-called 'irisin' hormone. So when muscles are made to move (i.e. to expand and contract) this stimulates the body into producing irisin, and this in turn assists the process of converting white tissue into healthy brown tissue.
The importance of having firm muscles in the arms and legs cannot be overemphasized; this provides the body with a good 'energy warehouse' that serves for everyday activities and for keeping us alive. Flabby (white tissue) muscles store much less energy than firm (brown tissue) muscles.
The greater your capacity to store energy, the greater your level of energy for work, rest and play. When you lack energy, you lose the motivation to be active and you eat more to compensate for generally feeling lack-lustre in your daily life - it's a vicious circle. When you have plenty of energy, you thrive in your daily life, food cravings and over-eating disappear, and you will be motivated to be normally active without becoming exhausted.
The Bostrom Study concludes that exercise increases irisin and that this in turn increases firm muscles with brown tissue. This in fact is so because any kind of sustained physical activity will do this. But it does not follow that exercise is in any way beneficial. Firm muscles can quite easily be developed by doing physical activities that do not make you breathless or sweaty, such as walking, swimming, dancing, rowing, lifting, pulling and pushing movements, all of which can be done without becoming breathless or sweaty.
The Bostrom Study does not differentiate between breathless/sweaty exercise and non-breathless/non-sweaty physical activity. Also, the study does not take into account the serious and harmful effects of exercise as explained in this book. Hence, doing exercise to improve muscles is like using a sledgehammer to crack a nut - it's not worth the health-risk.
Furthermore, giving irisin to an obese person will not in itself make that person less obese, as implied by the Bostrom Study. You become less obese through physical activity that increases the energy storage capacity of the muscles. Irisin is simply one of the many hormones that is triggered by the body as a result of the physical activity. Therefore, putting irisin into the body of an obese person who remains inactive will have no effect on weight loss.
Making your muscles firmer and more capable of storing more energy does indeed combat obesity because when you feel more energetic you will be more active, you will be less likely to over-eat and less likely to succumb to junk food. But the way to make your muscles firmer is by being physically active, NOT by doing exercise that makes you breathless or sweaty.
Journal of Obesity Study, 2013.
News headlines: Why Exercise Makes You Eat Less, Not More
"High intensity exercise suppresses subsequent ad-libitum energy intake in overweight, inactive men compared with those at rest. These findings also corroborate.... that a single bout of high-intensity exercise suppressed spontaneous energy intake in the subsequent 24 hours compared with either a single bout of lower intensity exercise or rest in obese adolescents". Source: A.Y. Sim, et al, High-intensity intermittent exercise attenuates ad-libitum energy intake, International Journal of Obesity (2013), 1–6.
This study prompted headlines to the effect that intermittent high intensity exercise can help you lose weight by suppressing appetite. But when you examine the detail of the study the following points arise:
1. The participants were not compared with random controls from the population at large. Rather, they were compared with in-house controls that participated in the trials, albeit without exercising. This throws some doubt on the Study's conclusions. Controls that take an active part in experimental trials are notoriously unreliable because they are influenced by the trials themselves.
2. It is well known that exercise inhibits hunger, both during the actual exercise and for some time afterwards (even up to day afterwards), particularly after intense exercise. But eventually, when the body has 'recovered' from the exercise, excess feelings of hunger will result in over-eating and body weight gain. The study monitored participants within short trial periods, but failed to check body-weight loss or gain once the trials were over, i.e. once the participants returned to their usual lives.
3. The Study monitored food consumption for participants and controls in order to assess appetite suppression. But the Study did not monitor overall body-weight gain or loss for participants and controls. For example, it would have been useful to record body weight for all participants and controls at the commencement of the study, and then again say one month after the termination of the study. As such the findings of the Study throw no significant light on weight management.
4. As with many studies, this Study failed to differentiate between exercise that makes you breathless and sweaty, and physical activity that does not. It would have been very interesting to see the results of any study into exercise that makes this differentiation.
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Here are some examples of the growing evidence that weight loss does not benefit from exercise:
"Training intensity was set at the heart rate associated with 50% of each woman's peak VO2 [equivalent to very slow jogging or fast walking]. In this study of previously sedentary, overweight or obese, postmenopausal women we observed no difference in the actual and predicted weight loss with 4 and 8 KKW of exercise (72 and 136 minutes respectively)". Source: Timothy S. Church, et al, 'Changes in Weight, Waist Circumference and Compensatory Responses with Different Doses of Exercise among Sedentary, Overweight Postmenopausal Women', February 2009, PLOS One, 10.1371/journal.pone.0004515.
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"If you're more physically active, you're going to get hungry and eat more. There is a widespread assumption that increasing activity will result in a net reduction in any energy gap [i.e. a net reduction in obesity]. When kids start to exercise, they end up eating more — not just a little more, but an average of 100 calories more than they had just burned". Source: K R Sonneville, et al, Total energy intake, adolescent discretionary behaviors and the energy gap, International Journal of Obesity (2008) 32, S19–S27; doi:10.1038/ijo.2008.203.