The Health Delusion: How to Achieve Exceptional Health in the 21st Century

CHAPTER 9

THE AGE OF THE SLOTH

OVERVIEW

· Is greed really to blame for the obesity epidemic?

· We shift our focus to the massive changes in our physical activity levels in recent decades and find them to be in terminal decline.

· Whereas dieting is doomed to failure, increasing our levels of physical activity is the key to slowing, and even reversing, the obesity time bomb.

· We look at how the effects of physical activity are not just limited to successful weight loss, but essential for promoting long-lasting health, too.

Now that we’ve exposed the fallacy of the fad diet, we want to deal with another canard. We hope you’re sitting comfortably… deep breath, here goes…

The population is not meant to be cutting back on food because we don’t have a problem with overeating. In fact, if anything, we are now eating less.

We know, we know. This is the ‘fast-food nation’, a population personified by gluttony, routine ingestion of a bonanza of calorie-laden drinks, fast food, sugary treats and supersized portions, all underpinned by an inability to know when we’ve had enough.

It’s hard to argue with this. After all, the message to ‘eat less’ has been relentlessly drummed home. But the fact is, the science just doesn’t back it up. A report from the UK Department for Environment, Food and Rural Affairs found that the ‘average energy intake per person was at least 20% lower in 2005–2006 than in 1974’¹. This is despite obesity rates more than trebling since the early 1970s. Figures for Canada from 1970 versus 1998 show a similar trend of increasing obesity paralleled by a notable overall decline in calorie intake².

A review of US national surveys found that the number of overweight people increased by 31% between 1976 and 1991, but calorie intakes were down 4% due to a rise in low-calorie food consumption³. Admittedly, this is at odds with the large NHANES study of the US population, which found that between 1971 and 2000, calories increased by 7% in men and 22% in women⁴. But the thing you need to know about these stats is that the jump in intake took place in the 1988–1994 survey period, when the survey was changed and questions added to get more complete answers, including – for the first time – calorie intake over the weekend. Considering that weekends are a common source of binge eating – on Saturdays we eat an average 12% more calories⁵ – a reported increase is hardly surprising. Americans weren’t eating more, the measurements were just getting better!

If we look at children and adolescents in the USA, there was no overall increase in calorie intake over the whole 30-year period⁶. Yet this is a population showing rapid rises in obesity, setting the stage for detrimental health impacts in adult life. China is also showing an alarming trajectory of weight gain. Once considered one of the world’s leanest populations, it now contributes a fifth of the world’s overweight and obese⁷. Yet surveys show that between 1989 and 2004 calorie intake has actually decreased consistently across cities, suburbs, towns and villages⁸.

We admit that this might be hard to swallow, especially as it’s been etched into our psyche that we’re just a greedy and gluttonous bunch who have munched our way into this sorry predicament. Still, the data is hard to refute; as nations we’re consuming the same or fewer calories than we were before rates of obesity soared. We should point out here that we’re referring to the population as a whole, and clearly there are some individuals who are eating too much. But take a step back and look at the bigger picture. It tells us that the blame for the bulging belly of the majority can’t be pinned on gluttony.

Lazy days

So, if calorie intake hasn’t increased in recent decades, how has calorie expenditure fared? The fact is that we’re much less active now than we were. Society has undergone remarkable changes and so has the way we go about our lives. The age of technology, for all the advances it has brought, has meant physical activity has been virtually factored out of our daily lives.

The things that have made the biggest dents in our energy expenditure include a decline in physical and manual work (now only 10% of men and 20% of women are in active occupations), and a greater reliance on motorized transport with corresponding reductions in walking and cycling (in 1952, the UK population cycled 23 billion km, compared to 4 billion km today)⁹. Add in common labour-saving devices, the use of lifts and escalators instead of stairs, and our choice of sedentary leisure activities (we now watch 26 hours of television a week compared to 13 hours in the 1960s), and we can see the ‘age of the sloth’ permeates every facet of our daily lives⁹. And while the individual changes appear trivial enough, add it all up and we get a shocking statistic: the difference between the activity levels of living 50 years ago and today is the equivalent of running a marathon a week⁹. And with that comes an incredible number of calories we are no longer burning.

Technology is great. We use it and we wouldn’t want to be without it (and we’re guessing you wouldn’t either). But unless we actually want to, we really don’t have to bother with the whole business of expending energy. We can roll out of bed, drive to work, take the elevator, sit at a desk all day, drive home, eat pre-prepared food, watch TV before rolling back into bed again, then do the same the next day, and the next.

The physical activity effect

It’s not difficult to see that for all its good, technology comes at a price. By effectively factoring physical activity out of our day-to-day lives, it paves the way to obesity. There’s a good deal of evidence that backs this up, too. A study of the EU member states found that active people were 50% less likely to be obese, and that obesity was strongly associated with a sedentary lifestyle and lack of physical activity, supporting the view that ‘a reduction in energy expenditure during leisure time may be the main determinant of the current epidemic of obesity’¹⁰. Then we have the NHANES study (1971–1992), which examined factors influencing cardiovascular mortality in the US population. Its intriguing finding was that ‘those who were obese and reported the least physical activity had the lowest caloric intake’¹¹. This tells us that eating less doesn’t guarantee you’ll be slim, and eating more doesn’t necessarily mean you’ll be overweight. What does matter is the amount of physical activity you do.

A study published in the prestigious medical journal The Lancet found that changes in activity levels of US girls during adolescence had a significant effect on changes in their BMI and fat levels. But was it more important than what they ate? The authors concluded that, while activity levels played an important role in determining weight gain, energy intake did not exert the same effect¹². It’s yet more evidence that physical activity is the trump card. In fact, a dose response relationship exists between exercise and fat loss. When sedentary individuals begin a regular exercise programme, the more they exercise, the greater the amount of weight – and fat – they lose. Without any changes to diet, just one hour of moderate-intensity exercise, performed three days per week, could halt and even start to reverse the tide of obesity¹³.

With this type of evidence, we don’t think it’s unreasonable to speculate that physical activity is protective against developing obesity, and that the dramatic declines in physical activity in recent decades go a long way to explaining the parallel rise in obesity.

Current rates of physical activity

Minimum recommendations state that we should be doing 30 minutes of moderate physical activity five times a week, or vigorous activity for 20 minutes, three times a week, or a combination of the two¹⁴. Such levels are associated with a multitude of health benefits, including reduced risks of cardiovascular disease, stroke, hypertension, type 2 diabetes, osteoporosis, obesity, colon cancer and breast cancer. Moderate-intensity exercise for more than three hours per week reduces the risk of mortality by an impressive 27%, while vigorous exercise of 20 minutes’ duration three or more times per week reduces mortality risk by 32%¹⁵. Mortality rates are more than 50% lower in those who meet both recommendations¹⁵. A dose response effect is observable, and increasing your physical activity levels above the minimum recommendations will confer even greater benefits. It is recommended that, ideally, we should try to do up to one hour of physical activity per day for additional calorie burning and health benefits¹⁶. Don’t think that the effects of exercise are limited to physical wellbeing, either. Studies show that regular exercise promotes better sleep, reduces depression, boosts self-confidence and increases our sense of wellbeing¹⁷.

To obtain the health benefits of moderate physical activity, a minimum of ten minutes of continuous activity is required. In other words, you can’t count the one- or two-minute walk to and from the car, even if you do it a few times a day.

The talk test is one of the best ways to measure intensity. If, during your activity, you can speak three or four words per breath, you are working at a moderate intensity. If you can only get one to three words per breath, you are most likely exercising at a vigorous intensity. If you can sing during your activity, it’s not intense enough to realize health benefits.

Yet, despite all these highly desirable effects, surveys show that less than half of adults in the USA¹⁸, and 39% of men and 29% of women aged 16 and over in the UK¹⁹, say they meet the minimum recommendations for physical activity. And if these figures aren’t bad enough, they actually paint a rose-tinted picture of the truth. When physical activity levels were objectively measured with an accelerometer, it was found that people were just kidding themselves. The figures shrunk to 5% or less who were actually reaching minimum recommendations for activity levels in both the USA²⁰ and the UK¹⁹. We’ve become so lazy that we’re now living in complete denial. Yet somehow we’re still intent on blaming food intake for our weight gain.

Is it better to train moderately for longer or harder for less time? It seems more vigorous activity has greater benefits for cardiovascular disease and mortality, independent of the contribution to energy expenditure.

‘High Intensity Interval Training’ looks set to be the next big thing. This involves doing several short bursts of high-intensity exercise (e.g. sprints) separated by periods of lower-intensity exercise (e.g. slow or moderate pace). The advantage is that you get all the benefits of a workout, but in a much shorter time.

The following table lists different activities and their average calorie expenditure per 30 minutes.

It is also recommended that aerobic activity be accompanied by muscle strength training exercises, such as resistance training and flexibility exercises, at least twice a week. This helps to build and conserve lean body mass, assists with enabling long-term participation in regular physical activity and promotes quality of life. Although this type of exercise is typically associated with the younger generation, it is especially important for older people to engage in it, too. The old adage ‘use it or lose it’ rings true, and strength training should be undertaken to prevent the seemingly inevitable loss of strength, energy and vigour with age. Performed regularly, this type of exercise builds muscles and bones, improves coordination and balance and prevents falls. In fact, it is one of the best ‘anti-ageing’ strategies of all.

If you perform resistance training and are consistently able to complete more than 10–12 repetitions and/ or you do not need to take a break (one to two minutes) in between sets, then your intensity is too low and the resistance (weight) needs to be increased.

Wolff’s law states that bones will adapt to the loads they are placed under. This is why weight-bearing exercise is particularly important for maintaining strong bones and warding off osteoporosis. Examples of weight-bearing exercises include brisk walking, running, aerobics, tennis and resistance training.

Strength training, when performed correctly, is now recommended to improve chronic conditions such as arthritis, diabetes, osteoporosis, heart disease, obesity and back pain.

Dieting or physical activity?

We’ve set out our stall and said that we don’t think dieting and excessive calorie restriction is the way to go. But where dieting falls down, physical activity steps up to the plate.

In the previous chapter, we discussed ‘adaptive thermogenesis’, and the idea that the body can dramatically reduce the amount of energy it expends when it loses weight by calorie deprivation (i.e. dieting). If you remember, we said that losing 10% of body weight can reduce the amount of energy the body uses by 20–25%. Well, it turns out that the vast majority of this decline, some 85–90%, is attributable to what’s called ‘non-resting energy expenditure’, or in simple terms, the body’s reduced ability to burn energy during physical activity²¹. This is because the efficiency of the skeletal muscles improves, reducing the amount of calories expended, especially during low-intensity activity. However, by using exercise as a means of weight loss, we target this very problem, increasing our non-resting energy expenditure and thereby avoiding the ‘banana skin’ of adaptive thermogenesis. And when it comes to resting energy expenditure, it appears that there is no compensatory decrease from exercise either, so it’s a ‘win–win’^22,23.

Physical activity trumps calorie restriction in other ways too. Weight loss caused by restricting calories reduces the levels of our active thyroid hormone, which has the knock-on effect of decreasing our metabolism (the rate at which the body burns energy). However, when the same weight loss is brought about by physical activity, this reduction in thyroid hormone levels doesn’t occur²⁴. Whereas dieting puts the brakes on our metabolism, correctly performed physical activity can actually boost metabolism, with the effects lasting for hours after we stop exercising^25,26,27.

If all that wasn’t impressive enough, the benefits of exercise even extend to the regulation of appetite. While dieting causes a backlash from the body, releasing appetite-inducing hormones to encourage weight regain as part of the ‘adiposity negative feedback’ system, no such effect is seen from exercise, and compensatory increases in hunger or food intake do not occur after exercise²⁸.

A RCT was performed in obese individuals to investigate the effects of a 700kcal deficit per day induced by either exercise (one hour of brisk walking and/or jogging) or calorie restriction²⁹. At three months, both groups had lost 7.5kg (about 8% of body weight), though the exercise group lost more fat. And while we know the net result of dieting is gradual fat gain seen from six to 12 months onwards, with exercise we see long-term sustained weight loss³⁰. It is thus unsurprising that members of the US National Weight Control Registry – individuals who have successfully achieved long-term, significant weight loss (averaging 32.3kg at the six-year mark) – are very active physically, with 70% exceeding minimum exercise recommendations. Nor is it surprising that those who were the most successful at weight loss were the most physically active^31,32.

Many studies suggest that exercise alone produces only modest weight loss. This is simply because insufficient exercise levels are undertaken to create a big enough calorie deficit. Meeting minimum exercise recommendations burns about 1,000 calories a week. For significant and sustained weight loss, the equivalent of six to seven hours of brisk walking, or three hours jogging (2,000–2,500kcals) per week is required³³.

So there you have it: the ability to lose large amounts of weight to match any diet, but without the all-too-familiar and inevitable weight regain that undoes all your hard work. Instead, you just get the accompanying ‘side effect’ of dramatic improvements in your health.

A great way to stay motivated in your physical activity regime is to set yourself attainable and relevant shortand long-term goals, and to reward yourself when you achieve them. Your success is dependent on setting goals important to you, and your desire to achieve them.

With the increased strength and fitness capacity obtained from exercise, we can progressively build up the intensity/duration of our activity and circumvent any stagnation in fat losses that may occur.

THE PARTING SHOT

The weight-loss industry has commandeered the snake-oil market in recent decades. With billions upon billions being spent on weight-loss ‘solutions’, this is seriously big business. Let’s face it, there’s not a whole heap of money to be made from telling people to increase their activity levels. It’s not a patch on the PR generated by the newest wonder diet endorsed by a Hollywood superstar (ironically, someone who looks great naturally, and probably hits the gym for hours each day anyway).

Who wants to sweat it out on the treadmill when you can just eat a particular diet – and be in ‘a phase’ or ‘the zone’ – shedding pounds while you lie on the couch watching the soaps? Unfortunately, as we now know, these diets don’t work. It’s time to accept that the emperor isn’t wearing any clothes and these zealously endorsed diets wreak havoc on our long-term wellbeing.

Lest our message be misconstrued, we’re not saying that you can eat what you like. After all, this whole book is about eating well. But don’t confuse eating an optimally healthy diet with ‘dieting’, and remember that long-term success requires permanent changes in lifestyle and physical activity habits, on top of a healthy, balanced diet.

SUMMARY AND RECOMMENDATIONS

· Contrary to popular belief, on the whole we’re not eating more than we were 30 years ago – a time before obesity rates were an issue.

· We may not be quite as greedy as we think, but we are more lazy – life in the modern world means physical activity levels have plummeted to an all-time low, paving the way to obesity.

· As well as stemming the tide of obesity, increasing our physical activity has an enormous range of other benefits for our physical and mental wellbeing.

· Aim to meet minimum recommendations of 30 minutes of moderate physical activity five times a week, accompanied by muscle strength training exercises at least twice a week.

· If you are already overweight or obese, you will need to go above these exercise recommendations to create a big enough calorie deficit for a significant weight-loss effect.

· While you should avoid ‘dieting’, you still need to combine increased physical activity with an optimally healthy diet to reap full weight- loss and health benefits.

· It goes without saying that you should seek professional advice before starting on any exercise regime, especially if you haven’t exercised for a long time or have a medical condition.