As we all know, weight loss diets are big business. And looking at the statistics, it's easy to see why. Currently, an estimated 58 million American adults are overweight (BMI 25+), of whom an estimated 40 million are obese (BMI 30+), 9.6 million are seriously obese and 6 million suffer from super-obesity (BMI 40+). Worldwide statistics on overweight are equally alarming, as reflected in the new word "globesity". In China, the number of overweight people has risen from less than 10 percent to 15 percent in just three years. In Brazil and Colombia, the figure of overweight is about 40 percent - comparable with several European countries. Even sub-Saharan Africa is seeing an increase in obesity, especially among urban women. In all regions, obesity appears to escalate as income increases. And the higher the incidence of obesity, the higher the incidence of weight-related disease, including: type 2 diabetes, cardiovascular disease, metabolic disorders like insulin resistance, and cancers of the breast and colon.
CONVENTIONAL DIET METHODS
Both the US Surgeon General and the Dietary Guidelines For Americans (2005) issued by the US Dept of Agriculture emphasise the need for calorie control and increased physical exercise to reduce the overweight epidemic, but evidence suggests that conventional diet methods do not provide significant weight reduction, due to poor compliance. Surveys show that annual weight loss resulting from convention diet and exercise programs averages less than 8 pounds per annum, while in a 4-year follow-up study of programs incorporating the use of obesity drugs, behavior modification, diet and exercise, the final average weight loss was 3 pounds. This apparent failure of conventional weight loss methods is often contrasted with the 30-40 percent average weight loss following bariatric surgery.
FOOD COMPOSITION OF DIETS
Fashion sells products, and weight loss diets are no exception. First we had low-fat diets, which were promoted as heart-friendly ways of reducing weight. Unfortunately, this message was interpreted by consumers as "all fats are bad, all carbs are good", and led to an unhealthy overconsumption of refined carbs. With the relaunch of Dr Atkins "New Diet Revolution", the fashion penduluum swung the other way. Now carbs were the enemy, not fat.
After Atkins came the South Beach Diet, which offered us a more moderate low-carb approach. Now, it is GI diets - based on foods with a lower glycemic response - that are high fashion and, being scientifically more beneficial, are likely to remain so for some time. However, while the food composition of diets may change, the basic law of weight loss remains unaltered: calorie expenditure must exceed calorie intake. To this extent, provided a diet is calorie-controlled and includes foods from all food groups, the exact composition of foods remains no more than a matter of personal taste.
GENERAL EATING AND EXERCISE HABITS
When assessing the effectiveness of conventional dieting methods, due regard must be paid to general eating habits. In America at least, these do not appear to be helpful. Despite the mounting evidence of weight-related ill-health, social eating habits continue to develop in unhealthy directions. Value-for-money "supersizing" continues to attract customers, while fast-food sales continue to rise. And the continuing demand for "instant" food only inspires the food industry to produce more and more refined food options bulging with nutritional deficiency and calorie-overload. Is it any wonder that levels of diet-compliance among average dieters is so low? Meantime, an estimated 78 percent of Americans do not meet basic activity level recommendations, while 25 percent are completely sedentary.
IS SUPPORT THE ANSWER?
If conventional diet programs remain less than perfect ways of tackling overweight in the face of engrained eating habits, it would be misleading to write them off completely. Not only does research data from the US National Weight Control Registry demonstrate that long term weight reduction is perfectly achievable, a number of diet programs, especially medically-supervised clinic-based programs, are consistently effective. What distinguishes these diets is the level of counseling support which subjects receive. Nowadays, this support can be provided in various ways, including: mandatory group meetings, one-on-one sessions, online forums or chat-rooms. And it seems to work. For example, according to recent studies, the average weight reduction for a 10-12 week clinic-based obesity program involving meal-replacement diets, exercise and counseling support is 5.5 pounds.
FINDING MORE SUPPORT
If getting proper support is one way of improving conventional diets, dieters need to rethink their approach. Instead of focusing attention on finding the optimal eating-plan, they need to look for programs offering optimal support. Weight Watchers is an obvious choice but diets organised around the workplace or other social groupings may also provide natural help. Online programs with forum support might also be considered. In any event, there is no substitute for a reliable dieting partner.
ADOPTING HEALTHY HABITS
Given the fact that losing as little as 7-10 percent of body weight can improve many of the problems linked to being overweight, such as high blood pressure and diabetes, some obesity experts advocate a less formal approach to calorie control. They recommend adopting certain healthy habits rather than following a specific diet. An example might be a 200-calorie-a-day reduction achievable by taking a moderate 30 minute walk, and switching from (say) whole milk to skimmed milk. This saves 73,000 calories a year - the equivalent of 20 pounds of body fat. The commercial response to this approach is already visible in programs such as the "Three Hour Diet", which recommends regular eating to maintain a regular rate of calorie burning. Expect to see more weight loss programs like this, which emphasise specific habits.
Current levels of overweight and obesity require urgent attention. To be effective, conventional diet programs need to provide optimal support rather than optimal food composition, in order to facilitate diet compliance. For people who are unable or unwilling to follow a specific weight loss plan, making small but specific changes may be sufficient to achieve significant improvements in health.
Linda Smyth B.Sc., RD, aged 51, is a qualified dietitian and nutritional consultant. She is part of the editorial team at www.diet-i.com which provides a range of information about diet, nutrition and weight management to more than 5 million visitors per year.