Obesity is killing us. So why can’t we do anything about it?
Canadian children spend an average of 7.5 hours a day in front of screens. On average, adults are sedentary for 10 waking hours per day. And we eat the equivalent of 26 tsp of sugar a day on average, 35% of which is artificially added.
Canada is facing rising obesity rates, and the problem extends worldwide. Over 600 million people around the world have obesity. This is a major health problem as obesity greatly increases the risk of diabetes, cancer and cardiovascular disease, the latter being the leading cause of death in the world.
There are over 100 factors that could affect people’s weight, including overeating, sedentary lifestyles and the environment we live in. It’s often assumed that obesity is caused by eating too much and moving too little, so to fight it, individuals just need to reverse both of these habits. Unfortunately, it’s not that simple.
People who have obesity are often depicted as lazy or weak-willed, but biological and environmental factors can undermine their attempts to lose weight. While a select few might be able to lose significant amounts of weight and keep it off by calorie restriction, most won’t be able to. Behavioral changes alone only results in a modest 3% to 5% weight loss, says Arya Sharma, medical director of the Alberta Health Services Obesity Program. And according to a recent study that gathered the electronic health records of over 150,000 people who have obesity in the U.K., the chance a person with obesity attaining a normal weight in any given year is one in 210 for men and one in 124 for women.
Knowing that the odds are stacked against individuals losing weight on their own, governments have turned their attention to population-level interventions such as higher taxes on soda, increasing physical education in schools and calorie counts on menus. But do they work?
The evidence behind population-based interventions in children
Many interventions focus on childhood – an opportunity to shape healthy habits before kids develop obesity. Since it’s so difficult to reverse obesity, preventative measures are considered important.
A Cochrane review found that obesity prevention programs had a small but beneficial effect on children’s body-mass index (BMI), with an average drop of -0.15. Those that targeted 6- to 12-year-olds were particularly effective. One of the most promising strategies was including healthy eating, physical activity and body image into school curricula. They also suggest improving the nutritional quality of food in schools, and providing support for both teachers and parents to implement health promotion strategies.
These results must be interpreted cautiously, though, because the diversity of each study makes it difficult to say with certainty what caused the weight loss. In summary, the authors said that the creation of an environment that cultivates eating right and exercising more is needed, and that we should now focus on determining the best population-level interventions that can be integrated into the school system and sustained in the long term.
Schools are not the only environments getting a healthy makeover. This year the Government of Ontario started the Healthy Kids Community Challenge, which asks 45 communities across the province to create local, evidence-based interventions that promote healthy behaviours in children. The challenge is based upon France’s EPODE program, the largest childhood obesity prevention program in the world.
EPODE is inspired by the success of another smaller program, conducted in two towns in France, which found a decrease in the proportion of children with obesity from 13% to 9% in two years. Their data suggests that, over a long period of time, interventions targeting all levels of a community can have “synergistic effects” on obesity. Based on these findings, EPODE suggests interventions targeting schools alone are not sufficient – the community must get involved, including local sports and parents associations, catering structures, health professionals, elected representatives, and local stakeholders from the public and private sectors.
Those interventions are fighting against established interests like the food industry. According to a series of papers published by The Lancet, exposing children to ultra-processed foods heightens their expectations of taste and contributes to their preferences for unhealthy products.
Obesity expert Yoni Freedhoff says we’ve normalized the sale of junk food for schools, sports teams, and even children’s hospitals. “Selling illness in the name of health is backwards,” says Freedhoff, founder of Ottawa’s Bariatric Medical Institute, which offers non-surgical interventions for people who have obesity.
Addressing adult obesity
Population-level obesity interventions for adults have less evidence behind them. One controversial example of this is taxes on sugary beverages. For the past two years, Mexico has implemented a tax of 1 peso per litre on sweetened beverages. After one year, the purchases of taxed beverages decreased by 12%, while the purchases of untaxed beverages, like bottled water, increased by 4%. However, there are many skeptics who say it is difficult to connect the decrease in consumption with the increase in tax, due to other factors like slow economic growth and changing consumer behaviour. It is also difficult to connect the sugar tax to weight-loss, because even if people are buying less soda, they might be compensating by eating other sugary foods. This might be why the average BMI in Mexico is still increasing.
Another popular intervention is calorie counts on menus. In 2017 the Ontario government will implement legislation that will require chain restaurants to post calories on their menus. A review of menu labelling done in the U.S., Canada and other similar countries says that this intervention is in its infancy, and that there is little evidence that this has any significant influence on consumers’ food choices. Despite this, the study does support the inclusion of easily interpreted nutrition information on menus along with calories, particularly to help people who may have limited food and health knowledge.
Health Canada is also proposing to revamp the nutrition facts box on prepackaged foods, making it simpler. Erin Hobin, a scientist at Public Health Ontario, conducted a study of young Canadians and found that standardizing serving sizes and adding more interpretive nutrition information improved young Canadians’ comprehension of nutrition facts tables, but more research is needed to find out whether this change causes more informed food choices or could lead to a reduction in obesity.
According to Cambridge Behavior and Health Research Unit, there is some evidence that environmental interventions, such as downsizing portions and making end-of-the-aisle supermarket displays healthier, can help reduce obesity. But overall, the evidence that adult interventions work is limited.
The reason for this may be that programs are being developed in isolation. Hobin, along with many other experts, believes there is no “silver bullet” intervention. But the cumulative effects of multiple population-level interventions working together might make the difference. Single interventions are like single sandbags – they can’t stop the flood of the obesity epidemic. But together, they might build a levy.
Reducing the health impacts of obesity
Even if interventions don’t reduce obesity, they can still make people healthier. Nutrition and healthy living are also ways to gauge success.
If someone who is exercising regularly doesn’t lose weight, they haven’t necessarily failed, says Mike Evans, a doctor at St. Michael’s Hospital who creates popular YouTube videos about health. Rather, they’ve succeeded in becoming more physically active.
And that’s important. Experts have established that exercise doesn’t help most people lose weight, but Yoni Freedhoff says, “exercise might not be the best drug for weight loss, but it is still the world’s best drug for health.” Studies show that it can dissipate some of the negative health effects of obesity, even if it doesn’t result in weight loss. People with obesity can lower their risk of death from any cause if they regularly engage in high-intensity fitness.
Similarly, even if a healthier diet doesn’t seem to be helping with weight loss, it is still beneficial. Arya Sharma, medical director of the Alberta Health Services Obesity Program, says there’s no evidence that eating five fruits a day will help someone lose weight, “but can we agree that everyone should eat more fruits and vegetables? Of course.”
Freedhoff is optimistic, saying that if interventions can help healthy choices become the norm, he says, the tide of obesity should start to recede.
He returns to the sandbag analogy, saying, “In a flood you don’t have the luxury of knowing which sandbag will be the most essential. We should just be stacking as many as we can, instead of arguing about the merits of each one.”