More than 6% of people in the US now have a BMI1 over 40 “and the trend is on its way to Europe” warned James Hill, executive director of the Anschutz Health and Wellness Center, Colorado University, at the International Sweeteners Association conference in Brussels last week (02-04-14).
Understanding the cause of obesity has therefore never been more important, Prof Hill told fellow health professionals because more than one third of adults are overweight and one third obese.
Headlines wrongly blaming specific foods and drinks for causing obesity are not helping people recognise that the basic cause of obesity and overweight is energy imbalance.
“Although energy balance is a little more complicated than the basic difference between calories consumed and calories expended,” explained Prof Hill, “but the energy balance system helps us know what to do.”
The complication is that many factors – not just one food or drink – can cause energy imbalance and weight gain, said Prof Hill.
“Increasing portion sizes, high energy density and high glycemic index foods, advertising, marketing, easy access to food, reliance on convenience; sedentary lifestyle and reduced calorie-burning physical activity are just some of the confounding factors and influences.”
“We are not bad at losing weight, but however successful our dieting we tend to regain weight over time. Prevention of weight gain is therefore the best solution,” said Prof Hill.
Rather than thinking in terms of dieting to lose weight, think of making changes to your diet and lifestyle in order to enhance your quality of life and be able to do and enjoy more, advised Prof Hill.
“Whether you want to prevent weight gain, or keep off weight lost maintaining an Energy Gap of 100 calories a day is the good move,” said Prof Hill citing as evidence the National Weight Control Registry comprising 10,000 “maintainers” who lost on average 70lb and who have kept the weight off for seven years.
“These people have a lot in common. They tend to eat a low fat diet (not more than 30% of calories), they self-monitor and have a plan for when their weight goes up too much, their food behaviour and habits are consistent, they have breakfast every day.
“They also expend high levels of physical activity – one hour a day and this last point is key to their success.”
For most people creating a daily 100 calorie deficit will prevent weight gain, explained Prof Hill. “Small changes make a big difference over time. Putting it another way, if people eat 100 calories more than they use each day they will gain 1.8lb or 0.82kg of weight a year, a typical adult weight gain. Obesity is a gradual thing that can grow out of small errors.”
“Building on small changes is easier and more likely to be maintained than making big changes,” said Prof Hill. “Physical activity is a good example. Even if you start by walking to the end of the drive each day, that is better than not taking any steps; and you can build from that.”
“As physical activity goes up, food intake may also go up but weight can stay the same, said Prof Hill. “Human biology works best at high levels of physical activity.”
“The best advice is the Eat Smart and Move More because few people can maintain a healthy weight while living a sedentary lifestyle.” Becoming sedentary encourages abdominal fat to accumulate and appetite control to become weaker.
“The Stealth Health approach is to make your default diet a healthy one and make better choices so that you can push back against the environmental and behaviour patterns that lead to weight gain.”
1 An ideal BMI is 18-24, overweight is 20-30 and obese is above 30. To work out BMI divide your weight in kilograms by height in metres squared.
*Janette Marshall, Nutrition and Health Journalist