I say losing fat as opposed to losing weight because the latter is too broad: if excess weight is due to larger muscle mass for example, it is (usually) far less troubling for health reasons. When people speak of losing weight, they really mean improving the ratio of fat to muscle in their bodies (hence the phenomenon of “skinny fat“, in which someone appears slim in both appearance and scale results, but has a disproportionate amount of fat relative to muscle).
With all that cleared up, I know what many people are thinking: another study countering what so many other studies have previously established. This seems to be a perennial problem in nutritional science, which is still a young and developing field full of unknowns and rife with difficulties in conducting research (there are so many variables affecting health and weight among individuals that it takes unfeasible large and long-term studies to get solid, measurable results — hence why so many conventional wisdoms are being challenges decades later following the build-up of many studies).
Anyway, take the following report in the Washington Post as you will. From what I have read on the subject, the claims of these researchers do seem well-substantiated, but feel free to present your own arguments.
A growing body of scientific evidence shows that exercise alone has almost no effect on weight loss, as two sports scientists and I described in a recent editorial in the British Journal of Sports Medicine. For one, researchers who reviewed surveys of millions of American adults found that physical activity increased between 2001 and 2009, particularly in counties in Kentucky, Georgia and Florida. But the rise in exercise was matched by an increase in obesity in almost every county studied. There were even more striking results in a 2011 study published in the New England Journal of Medicine, which found that people who simply dieted experienced greater weight loss than those who combined diet and exercise.
How can this be explained? When people exercise, they stimulate their appetites, spurring them to eat more than they would have without working out. People also assume that expending more energy necessitates higher calorie intake, but they often overestimate how much. In reality, if you exercise for the purpose of burning calories, you get a very low return on investment: You would have to walk for more than 45 minutes to burn off the 300 calories from eating just three cookies.
On top of that, the idea that physical activity speeds up our metabolism so our bodies consume calories more quickly is exaggerated. In a study published in 2012, a group of anthropologists measured the daily physical activity, metabolic rates and energy expenditure of people in a hunter-gatherer tribe in Tanzania, and compared the results to the average Westerner. Though the Tanzanian subjects were more physically active than Westerners, their metabolic rates were similar. In other words, the researchers concluded, “active, ‘traditional’ lifestyles may not protect against obesity if diets change to promote increased caloric consumption”
Trial evidence consistently reveals that basal metabolic rates tend to drop as people lose weight, despite daily exercise. A comprehensive 2013 literature review by Amy Luke, a public health scholar at Loyola University of Chicago, concludes that “numerous trials have indicated that exercise plus calorie restriction achieves virtually the same result in weight loss as calorie restriction alone”.
I am sure most of us who have tried to get into shape (myself included) can relate with these observations; they don’t call it “working up an appetite” for nothing. Our bodies were evolved to consume and retain as many calories as possible. Trying to lose weight simply does not make sense from an evolutionary point of view: for most of human existence, a state of resource scarcity and insecure food supply was the norm, so why would we ever need to worry about excess weight? We needed all we can get.
A millennium of this arrangement is not suddenly going to wear off following just a century or two of a large minority of humans enjoying food abundance. There is a reason why obesity is a global problem, growing to some degree or another in just about every country (including those still developing). It a fundamentally human problem.
It’s calorie intake that is really fueling the obesity epidemic. But it’s not just the number of calories we’re eating as how we’re getting them. The sugar calories are particularly bad. Stanford University researcher Sanjay Basu recently led an analysis of 175 countries that evaluated the amount of sugar in each nation’s food supply. As sugar availability increased by 150 calories per person per day (the equivalent of a can of cola), there was a 1.1 percent rise in the prevalence of Type 2 diabetes in the population — an increase that was 11 times larger than if people consumed 150 more calories from nonsugar sources — independent of average body mass index and physical activity levels. The experience of Timothy Noakes, a leading sports and exercise medicine scientist, exemplifies those results. Despite being an almost daily runner and completing more than 70 marathons in his lifetime, Noakes developed Type 2 diabetes in his late 50s, which he attributes to his excessive consumption of sugar and other refined carbohydrates…
…None of this means you should turn in your gym membership card. Working out will make you healthier and less susceptible to disease. No matter what your size, even 20 to 30 minutes of physical activity that breaks you into a sweat five times per week will substantially improve your health and well-being. Do what you enjoy, whether it’s dancing, cycling, sex or all three. If it’s longevity you’re after, note that elite athletes in high-intensity sports don’t live any longer than top golfers.
But if weight loss is your goal, your diet is what really needs to change. An analysis by professor Simon Capewell at the University of Liverpool revealed that poor diet (for example, eating too much junk food without enough nuts, whole grains, fruit and vegetables) now contributes to more disease and death than smoking, alcohol and physical inactivity combined. And up to 40 percent of those with a normal body mass index harbor metabolic abnormalities that are associated with obesity, including high blood pressure, nonalcoholic fatty liver disease and heart disease.
There is more than evolution and biology at work, however: as a social species, we are deeply impacted by our communities and environments. So growing up in a world where abundant food, ubiquitous advertising, and large portions are the norm makes eating a lot, and eating poorly, socially conditioned — and difficult to resist. Willpower can only get you so far when your body is evolved to eat as much as you can, and widespread marketing is determined to ensure that.
Sadly, many doctors’ understanding of nutrition is influenced by bogus industry advertising. In July 2012, I stopped drinking the popular sports drink Lucozade after Oxford University researchers found a “striking lack of evidence” to support claims that such products enhance performance and recovery. Instead of wasting close to $10,000 over the previous 15 years drinking a product loaded with seven teaspoons of sugar, I would have been better off drinking tap water at the gym. The World Health Organization now recommends no more than six teaspoons of sugar a day for the average adult.
Misconceptions about diet and exercise are paralyzing efforts to curb the worsening obesity crisis. The food industry has been central in pushing these misconceptions, using tactics similar to those employed by big tobacco, to elide its culpability in spreading disease. In a 2009 paper published in the Milbank Quarterly, a public health journal, researchers found that the food industry has formed close ties with influential politicians and scientists who give it powerful avenues to quash policies and research that highlight the harms of sugar. This strategy also allows it to push the message that personal responsibility and a lack of physical activity are really at the root of public’s obesity problem. Reuters found that the food and beverage industry spent more than $175 million on lobbying during President Obama’s first three years in office, more than doubling its spending under the last three years of George W. Bush’s administration, targeting proposals like a federal tax on sodas and stricter nutritional guidelines.
Corporate greed and a systematic political failure to protect citizens from the manipulations of the food industry have brought American health care to its knees. More than 75 percent of health-care costs now go toward treating chronic metabolic diseases and their associated disabilities. These problems are a result of food industry spin and false information linking physical inactivity and obesity. Curbing the global obesity problem will require changing what we eat, not selling more pedometers and exercise videos. The bottom line: You can’t outrun a bad diet.
All this suggests that a large part of reducing obesity will — not doubt controversially — require social and even political solutions. Somehow, we will need to change the way food is marketed, and perhaps even seek to reduce the amount of processed or unhealthy food out there in the first place (reigning in on all those agricultural subsidies, which lead to an abundance of corn and its derivatives, would be a good start).
But the idea of the state deciding how markets should operate is anathema to the U.S., and indeed many other cultures. Of course, it might not be necessary if the private sector changes its approach and puts more emphasis on healthier food. But that in turn will not happen if there is a lot of money to be made pushing unhealthy food with high profit margins. Perhaps as public consciousness grows regarding the importance of a healthy diet, there will be pressure put upon the industry to change what sorts of food and drink it produces and markets.
But given the intersection of evolution, social conditioning, a deep-seated and pervasive consumer culture,and economic incentives, it is going to be tough for individuals and communities alike to eat healthier. A lot of things would have to change on a macro level, and it would be both costly and contentious. What are your thoughts regarding solutions and approaches?