Obesity, defined as a body mass index (BMI) of 30 or above, increases the risk of a multitude of chronic health conditions including Type 2 diabetes, hypertension, coronary heart disease, endometrial, breast, and colon cancers, dyslipidemia (high cholesterol and triglycerides, stroke, liver and gallbladder disease, sleep apnea and respiratory problems, and osteoarthritis of the knee. It is now understood that most people do not gain large amounts of weight at once – rather, people usually gain a few pounds a year until they find themselves facing a cumulative substantial weight gain many years down the road. This is exacerbated by the unfortunate fact that metabolism slows as a result of the aging process, leading to increased difficulty in weight loss as one gets older. In fact, in order to maintain the same weight as we age requires reduced calorie intake/increased physical activity. For this reason, it is always better to circumvent weight gain in the first place.

Sleep fulfills the following three major functions:

• It serves as the energy restoration period from daytime activities
• It affords bodily protection at night when sensory capacities are down-regulated
• It allows the brain to consolidate experiences and memories for learning

Geoff Colvin, in his book Talent is Overrated, writes about a study of violinists at an elite music school which tried to answer the question of why some musicians are better than others. The study looked at three different groups: the very best students, the good students, and students in a separate program stream that had lower admission standards. Although Colvin’s book actually examines the concept of deliberate practice in success, not sleep, it was interesting to note that the top group of violinists slept more than the other two groups.

In terms of obesity, other contributing factors have been identified. Chronic sleep deprivation, exceedingly common in today’s Western world, has been recognized as one of the causes of obesity. It is also possible that obesity itself may impact on the quality and duration of sleep. Most adults require 7-8 hours of sleep, and chronic sleep debt is defined as having more than 4 but less than 7 hours per night. I am not speaking of acute sleep deprivation, which happens infrequently during long travels, scrambling to finish a piece of work last minute, or waking up with a sick child. Chronic sleep is exactly that: long periods of time in an individual’s life when insufficient sleep is experienced.

The three major processes linking chronic sleep restriction to obesity are metabolic and neuroendocrine function, glucose regulation and waking behaviour.

Metabolic and Neuroendocrine Function

It has been found that chronic sleep restriction elevates the sympathetic nervous system, increasing evening cortisol production. This in turn can increase food intake and the accumulation of abdominal fat. In addition, sleep debt is associated with lower levels of leptin secretion. Leptin is secreted from fat cells and transmits energy balance messages to the hypothalamus (the brain centre for hunger). As leptin levels decrease, the hypothalamus interprets the message that the fat cells need more food and directs the body to eat more. Moreover, insufficient sleep leads to a significant increase in ghrelin, a hunger hormone produced and secreted from the stomach. Higher than normal circulating ghrelin levels stimulate hunger and food intake.

Glucose Regulation Processes

Chronic sleep deprivation is connected to impaired glucose metabolism, leading to a strong association between sleep debt and diabetes. Impaired glucose regulation is often coupled with weight gain – glucose plays an important role in regulating appetite. When glucose metabolism is compromised, which occurs with sleep debt, glucose utilization in parts of the brain becomes impaired. This promotes the hunger response.

Waking Behavior

This is simple – more time awake means more opportunities to eat. Due to the ubiquity of technology people often find themselves awake later than they would have been in years past. Moreover, many people find themselves tired during the day precisely because of inadequate sleep, and compensate for this by consuming caffeinated beverages to stay alert. This creates a vicious cycle in which it then becomes difficult to fall asleep at night.

References:

Colvin, G. (2008). Talent is Overrated. Penguin: USA.

Kravitz, L. (2010). Chronic sleep restriction is a risk factor for obesity. IDEA Fitness Journal, pp. 21-23.

Exercise Specialist Recommendations:

• Set a regular bedtime and stick to it.
• Do not consume caffeine after 1pm.
• Avoid exposure to bright light, television, computer, or tablets one hour before bedtime.
• Avoid stimulating conversations, either in person or by phone, one hour before bedtime.
• Do not do work one hour before bedtime.
• Limit naps to 30 minutes, and try to take them earlier in the day.
• Exercise in the mid or late afternoon – this has been shown to have positive effect on sleep quality.
• Do not smoke or use nicotine before bed, as nicotine keeps many people awake.
• Sleep in a very dark room.
• Block out noise with earplugs.
• Keep ambient temperature cool.
• Avoid drinking lots of fluids after dinner.
• Establish a relaxing bedtime routine that might include reading, drinking herbal tea, quiet time with your partner if applicable, and mediation or simple deep breathing.

Changing behaviour of any sort is very hard to do – but diligent adherence to the above set of recommendations will enable the chronically sleep-deprived to learn what it feels like to be truly well-rested. Once this experienced, there is no turning back.

Walking and running are the most popular physical activities for American adults. However, it has long been debated whether one is preferable to the other in terms of improving health. Now a variety of new studies that compared running directly against walking are providing some answers. Their conclusion? It depends on what you are hoping to accomplish.

For those whose goal is weight control running is superior. In a study published last month in Medicine & Science in Sports & Exercise titled “Greater Weight Loss From Running than Walking,” researchers combed survey data from 15,237 walkers and 32,215 runners enrolled in the National Runners and Walkers Health Study — a large survey being conducted at Lawrence Berkeley National Laboratory in Berkeley, California. Participants were asked about their weight, waist circumference, diets and typical weekly walking or running mileage both when they joined the study, and then again up to six years later. The runners were almost uniformly thinner than the walkers when each joined the study, and they stayed that way throughout. That is to say, over the years the runners maintained their body mass and waistlines far better than the walkers. The difference was particularly notable among participants over 55. Runners in this age group were not running a lot and, in general, were barely expending more calories per week during exercise than older walkers. However, their body mass indexes and waist circumferences remained significantly lower than those of age-matched walkers.

Why running should better aid weight management than walking is not altogether clear. It might seem obvious that running, being more strenuous than walking, burns more calories per hour. But in the Berkeley study and others, when energy expenditure was approximately matched — when walkers head out for hours of rambling and burn the same number of calories over the course of a week as runners — the runners seem able to control their weight better over the long term. One reason may be the effect of running on appetite, as another intriguing, if small, study suggests. In the study, published last year in The Journal of Obesity, nine experienced female runners and 10 committed female walkers reported to the exercise physiology lab at the University of Wyoming on two separate occasions. On one day, the groups ran or walked on a treadmill for an hour. On the second day, they all rested for an hour. Throughout each session, researchers monitored their total energy expenditure. They also drew blood from their volunteers to check for levels of certain hormones related to appetite. After both sessions, the volunteers were set free in a room with a laden buffet and told to eat at will. The walkers turned out to be hungry, consuming about 50 calories more than they had burned during their hour long treadmill stroll. The runners, on the other hand, picked at their food, taking in almost 200 fewer calories than they had burned while running. Blood tests demonstrated that, after exercising, the runners had significantly higher blood levels of a hormone called peptide YY, which has been shown to suppress appetite. Conversely, the walkers did not have increased peptide YY levels, their appetites remaining hearty.

On other measures of health, however, new science shows that walking can be at least as valuable as running — and in some instances, more so. A study published this month that again plumbed data from the Runners and Walkers Health Study found that runners and walkers had equally diminished risks of developing age-related cataracts compared with sedentary people, an unexpected but excellent benefit of exercise.

Finally, in possibly the most reassuring of the new studies, published last month in Arteriosclerosis, Thrombosis and Vascular Biology and again utilizing numbers from the Runners and Walkers Health Study, runners had far less risk of high blood pressure, unhealthy cholesterol profiles, diabetes and heart disease than their sedentary peers. But the walkers were doing even better. Runners, for instance, reduced their risk of heart disease by about 4.5 percent if they ran an hour a day. Walkers who expended the same amount of energy per day reduced their risk of heart disease by more than 9 percent.

Of course, few walkers match the energy expenditure of runners. “It’s fair to say that, if you plan to expend the same energy walking as running, you have to walk about one and a half times as far and that it takes about twice as long,” said Paul T. Williams, a staff scientist at Lawrence Berkeley National Laboratory and the lead author of all of the studies involving the surveys of runners and walkers. On the other hand, people who begin walking are often more unhealthy than those who start running, and so their health benefits from the exercise can be commensurately greater. “It bears repeating”, Dr. Williams said “that either walking or running is healthier than not doing either”.

For confirmation, consider one additional aspect of the appetite study. The volunteers in that experiment had sat quietly for an hour during one session, not exercising in any fashion. And afterward they were famished, consuming about 300 calories more than the meager few they had just burned.

Reference:

Reynolds, Gretchen. Is It Better to Walk or Run? The New York Times, May 29 2013.

Exercise Specialist Recommendations:

• Walk as much as possible.
• Run if you are able.
• Understand that the most important factor in good health is staying physically active throughout the lifespan. With this in mind, create a workout routine that is enjoyable, and most importantly, sustainable over the long term.
• Lift weights! Strength training sustains and/or improves stamina (which declines with age) - this makes long term exercise adherence more likely.

It is no secret that we have been battling a major obesity epidemic in North America for the last 20 years or so. Research shows that two-thirds of Americans are overweight or obese (Ogden et al. 2014), a health condition associated with hypertension, cardiovascular disease, diabetes, depression and various cancers (breast, endometrial, colon and prostate) (Malik, Schultz & Hu 2006). Furthermore, studies find that individuals tend to gain weight slowly over time after age 50—adding approximately 1 pound per year (Mozaffarian et al. 2011). Obesity is not exclusive to North America, however. In 1995, there were an estimated 200 million obese adults worldwide and another 18 million children under the age of 5 classified as overweight. As of 2000, the number of obese adults has increased to over 300 million. Contrary to conventional wisdom, the obesity epidemic is not restricted to industrialized societies; in developing countries, it is estimated that over 115 million people suffer from obesity-related problems.

In the US, obesity-related health care costs $190 billion annually, representing five to ten percent of all medical spending. Roughly half of these costs are paid through public expenditures. The medical costs for people who are obese are dramatically higher than those of normal weight (CSPI, 2015).

With this in mind, what are the main factors that cause people to gain weight? There are six factors that predict weight gain over the North American lifespan. 


Eating High-Calorie Foods

Eating behaviors associated with progressive weight gain over multiple 4-year periods included regular consumption of 


• potato chips and potatoes (french fries; mashed, baked and boiled potatoes);

• red meat, processed meats (bacon, salami, sausage and luncheon meats) and unprocessed red meats (beef, hamburger, pork, lamb or game);

• butter, sweets and desserts;
• and
refined grains (foods like white flour and white rice).

There are foods that help with weight management. Eating foods such as nuts, whole grains, fruits, vegetables, yogurt, diet (zero-calorie) soda, cheese and milk (low-fat, skim and whole) appeared to curb weight gain. These foods have slower digestion rates (some being high in fiber) and appear to enhance satiety—the feeling of being full after a meal. These foods can replace other, more highly processed foods in the diet, creating a reasonable biological mechanism whereby people who eat more fruits, nuts, vegetables and whole grains may gain less weight over time (Mozaffarian et al. 2011).


Consumption of Sugar-Sweetened Beverages

Sugar-sweetened beverages (SSBs) have little nutritional benefit and are reportedly the greatest provider of kilocalories in the American diet (Dennis, Flack & Davy 2009). In 2006, Malik, Schultz & Hu concluded that these drinks accounted for approximately 8%–9% of total energy intake in children and adults. SSBs contain carbohydrates of various forms, such as high-fructose corn syrup, sucrose and artificial sweeteners. Drinking SSBs has little impact on satisfying hunger (Malik, Schultz & Hu 2006), so people can consume large quantities without suppressing their appetite (Mattes 2006). 


The body’s response to carbohydrate (of equal caloric value) differs depending on whether it is liquid or solid. In a crossover study, DiMeglio & Mattes (2000) found that people who drank SSBs gained significantly more weight than they did when consuming a comparable amount of carbohydrate in solid form. Subjects participated in both treatments, following each for 4 weeks, and the SSB treatment produced double the fat mass compared with the solid-carbohydrate intervention. Both carbohydrate sources were the caloric equivalent to three 12-ounce sodas per day in both treatments (DiMeglio & Mattes 2000).

According to extensive research compiled by the Centre for Science in the Public Interest (CSPI), an extra soft drink a day increases a child’s risk of becoming obese by about 60 percent; and adults who drink one sugar drink or more per day are 27 percent more likely to be overweight or obese than non-drinkers, regardless of income or ethnicity. In addition, people who consume sugar drinks regularly—one to two cans a day or more—have a 26 percent greater risk of developing type 2 diabetes than people who rarely consume such drinks. The risks are even greater for young adults and Asians. Furthermore, daily consumption of sugar drinks for six months increases fat deposits in the liver by 150 percent, which directly contributes to both diabetes and heart disease (CSPI, 2015)

Sleeping Too Little, or Too Much

Although more clinical trials are needed, several epidemiological studies suggest that weight gain is influenced by sleeping less than 7 hours or more than 8 hours per night (Marshall, Glozier, and Grunstein 2008). According to Marshal and colleagues, people who sleep too little develop chronically impaired glucose metabolism, steadily contributing to obesity. In addition, sleep deprivation significantly lowers circulating levels of the hormone leptin and increases circulating levels of the hormone ghrelin—both effects that promote food intake.


Altering the regulation of these hormones contributes to increased hunger and appetite, especially for carbohydrate-rich foods linked to weight gain (Van Cauter et al. 2008). Sleeping 7 to 8 hours each night contributes to a successful weight management program.


Excessive TV Watching

Length of time spent watching television is highly correlated with weight gain, especially in young people (Chapman et al. 2012). Chapman and associates tell us 58.9% of Americans watch television for more than 2 hours per day. According to these authors, epidemiologic studies reveal that those who regularly watch more daily television per day tend to

• snack more while watching;

• have higher overall caloric intake of foods; and
• consume more energy-dense foods.

All these choices lead to weight gain. Conversely, children watching less than one hour of TV a day are associated with lower body weight, body mass index, skinfold thickness and fat mass, emphasizing the importance of lifestyle in weight gain (Chapman et al. 2012).


Overconsumption of Alcohol

Alcohol is very energy-dense—at 7 kcal per gram, it is second only to fat, with 9 kcal per gram; this creates a multitude of health issues. Aside from the pharmacological effects on the brain and on hormone fluctuation, the additional kilocalories from alcohol do not seem to replace energy consumption from other sources (Yeomans 2010). Therefore, energy consumption from alcohol augments overall daily calorie intake. 


Yeomans adds that alcohol consumed before or with meals tends to increase food intake, probably by enhancing the short-term rewarding effects of food. Uniquely, Yeomans cites epidemiological data suggesting that alcohol in moderation can protect against obesity, specifically in women. This means that alcohol is can be considered dose-dependent and should be monitored closely, especially while eating.


Not Engaging in Enough Physical Activity

In studying 15-year trends, scientists have noted an inverse relationship between walking and weight gain (Gorden-Larsen et al. 2009), suggesting that the more people walk, the less likely they are to gain weight. The researchers point out that older Amish people who walk an average of 18,000 (men) and 14,000 (women) steps a day have very low rates of obesity. They suggest that adding 2–4 hours of walking per week is an attainable movement target.


Despite the documented benefits of exercise, only half of Americans (51.6%) participate in the recommended volume (150 minutes per week) of moderate aerobic activity during the week, while only 29.3% do muscle-strengthening activities at least 2 days per week. Furthermore, just 20.6% of U.S. adults (23.4% men and 17.9% women) meet both the aerobic and muscle-strengthening guidelines (CDC 2011). This data can be extrapolated to Canada. This means that the majority of North Americans trying to lose or maintain weight will struggle because they are not meeting the minimum physical activity guidelines.


Exercise Specialist Recommendations:

• Watching too much TV or other screens, not getting enough sleep, drinking too much alcohol and too many sugar-sweetened beverages, eating high-calorie foods and eschewing physical inactivity indicate an obesogenic lifestyle and should be targeted in a behavior-change plan designed to prevent weight gain.
• For many people, changing one element at a time is less stressful and engenders a more successful outcome than trying to address all factors simultaneously.
• Successfully changing one factor can create cross-over success in other areas. For example, drastically reducing alcohol intake by itself can result in weight loss, making exercise more comfortable.
• Success can by stymied by an unsupportive environment. Try your best to get loved on board with your efforts, or join an online community of others who are engaged in behavioural lifestyle change.
• Weight training for a period of time (for example, 8 weeks) can build up strength and stamina, making cardiovascular exercise such as walking better tolerated.
• Do whatever you must to protect sleep. Sleep in a very dark room, go to bed at the same time each night, wear earplugs if your sleep is interrupted by a noisy bed partner, and avoid blue-lit screens (phone, ipad, computer) in the hour before bed.
• Eschew sugar-sweetened drinks at all costs, and make consumption of these a very occasional treat. If you enjoy Coke, share one can with a friend/partner a week. Sugar-sweetened drinks are deadly. Artificially-sweetened drinks are also to be avoided, as recent research shows that they impair glucose metabolism as well, and may lead to increased caloric intake from other foods.
• Know that weight management is a long- term prospect. If you are over 50, be realistic and focus your efforts on weight maintenance, instead of weight loss.

References:

CDC (Centers for Disease Control and Prevention). 2011. Adult participation in aerobic and muscle-strenghthening physical activities--United States, 2011.

Morbidity and Mortality Weekly Report, 62 (17), 326-30.Chapman, C.D., et al. 2012. Lifestyle determinants of the drive to eat: A meta-analysis. American Journal of Clinical Nutrition, 96 (3), 492-97.

CSPI (2015). Facts on Health Risk of Sugar Drink. https://cspinet.org/eating-healthy/foods-avoid/sugary-drinks. Retreived on July 22, 2015.

Dennis, E.A., Flack, K.D., & Davy, B.M. 2009. Beverage consumption and adult weight management: A review. Eating Behaviors, 10 (4), 237-46.

DiMeglio, D.P., & Mattes, R.D. 2000. Liquid versus solid carbohydrate: Effects on food intake and body weight. International Journal of Obesity, 24 (6), 794-800.

Gordon-Larsen, P., et al. 2009. Fifteen-year longitudinal trends in walking patterns and their impact on weight change. American Journal of Clinical Nutrition, 89 (1), 19-26.

Malik, V.S., Schulze, M.B., & Hu, F.B. 2006. Intake of sugar-sweetened beverages and weight gain: A systematic review. American Journal of Clinical Nutrition, 84 (2), 274-88.

Marshall, N.S., Glozier, N., & Grunstein, R.R. 2008. Is sleep duration related to obesity? A critical review of the epidemiological evidence. Sleep Medicine Reviews, 12 (4), 289-98.

Mattes, R. 2006. Fluid calories and energy balance: The good, the bad, and the uncertain. Physiology & Behavior, 89, 66-70.

Mozaffarian, D., et al. 2011. Changes in diet and lifestyle and long-term weight gain in women and men. The New England Journal of Medicine, 364 (25), 2392-2404.

Ogden, C.L., et al. 2014. Prevalence of childhood and adult obesity in the United States, 2011-2012. Journal of the American Medical Association, 311 (8), 806-14.

Purdom, T et al. (2015). The Science of Weight Gain. IDEA Fitness Journal, July 14.

Van Cauter, E., et al. 2008. Metabolic consequences of sleep and sleep loss. Sleep Medicine, 9, Supplement 1, S23-s28.

World Health Organization. http://www.who.int/nutrition/topics/obesity/en/. Retrieved on July 22, 2015.

Yeomans, M.R. 2010. Alcohol, appetite and energy balance: Is alcohol intake a risk factor for obesity? Physiology & Behavior, 100, 82-89.

Is it an urban myth that exercise improves sleep? No, according to the National Sleep Foundation’s 2013 report Sleep in America. By polling adults aged 23-60, it was learned that:

• More than 75% of exercisers reported good or fairly good sleep in the weeks leading up to the poll, compared to 56% of the non-exercisers.
• The majority of vigorous exercisers – defined as those who participate in cycling, swimming, running, or any competitive sports – rarely experienced insomnia symptoms. Half of non-exercisers said they woke during the night, and 24% had difficulty falling asleep every night or almost every night.
• Paradoxically, the non-exercisers tended to feel the most “sleepy” on a regular basis and to have more symptoms of sleep apnea.
• Those who sat for less than 8 hours per day were more likely to report “very good” sleep quality than those who sat for longer periods of time.

In the words of poll task force member Barbara A. Phillips, MD, MSPH, FCCP, “Exercise is beneficial to sleep. It’s time to revise global recommendations for improving sleep and put exercise…at the top of our list of healthy sleep habits”.

However, the relationship between sleep and exercise for people who suffer from chronic insomnia is more complicated. Aerobic exercise performed during the day won’t translate into better sleep that same night, according to Kelly Glazer Baron, a clinical psychologist and director of the behavioral sleep program at Northwestern University Feinberg School of Medicine. “It’s a long-term relationship. You have to keep at it and not get discouraged.” Most studies on the daily effects of exercise and sleep have been done with healthy sleepers, and Dr. Baron’s research is the first to demonstrate that aerobic exercise during the day does not result in improved sleep that same night when people have pre-existing sleep problems. Moreover, while poor sleep does not alter aerobic capacity it does make exercise feel much harder – which often prevents poor sleepers from adhering to an exercise program over the long term. Sleep and exercise have a positive influence on each other, and those who do not sleep well will probably not feel motivated to exercise.

So how does a person with insomnia reap the benefits of regular exercise on sleep patterns? Commit to an exercise program for 16 weeks. Through an analysis of sleep data from 11 women aged 57 to 70 from a 2010 clinical trial, Dr. Baron demonstrated the ability of aerobic exercise to improve sleep, mood and vitality over a 16-week period in middle-age-to-older adults with insomnia. People with insomnia have a heightened level of brain activity and it takes time to re-establish a more normal level of activity that facilitates sleep. As opposed to medications which induce sleep rapidly, exercise is probably a healthier way to improve sleep because it may address the underlying problem. For older adults – particularly older women, who have the highest rate of insomnia of any group - implementing an exercise program may be the safest approach because many sleep medications cause memory impairment and increase the risk of falling.

References:

National Sleep Foundation. Sleep in America. https://sleepfoundation.org/sleep-polls-data/sleep-in-america-poll/2013-exercise-and-sleep.

Baron, K.G., Reid, K.J., Zee, P.C. Exercise to Improve Sleep in Insomnia: Exploration of the Bidirectional Effects. Journal of Clinical Sleep Medicine, 2013 DOI: 10.5664/jcsm.2930