It seems that everyone has a pet theory on how “people” (especially other people) should go about losing weight. The whole popular culture seems to be convinced that everyone has to lose weight. The popular media is full of one-sided, one-size-fits-all advice on losing weight. Many among us are quite outspoken about how others should be going about it- as if one type of program would be a magic cure for every person’s overweight.

However, new research-based studies in peer reviewed professional journals show that there may be many causes of overweight and that there may therefore be many different treatment strategies needed throughout this heterogeneous population. In fact, the current literature honestly concludes that “simple, effective strategies for long-term weight loss and maintenance elude us”.

Despite the lack of a clear strategy for weight loss and maintenance, it would be nice to know which treatments show the most promise. Below we will cover the six major types of treatments and provide the information that is currently known about their effectiveness. These treatment types are: dietary, physical activity, behavioral, pharmacotherapy, surgical and genetic interventions.

Dietary

Restrictions on calorie intake combined with exercise or alone in order that the person will eat fewer calories (or “energy”) every day than they use is the most basic foundation of weight-loss programs.  “Low-fat”, “Low-carbohydrate”, “Very Low-Calorie”, and “Mediterranean diets” have been studied. Current findings have shown that weight loss depends much more upon restricting total calories consumed than on modification of the type of food eaten. Participation in any lower-calorie program or diet with a long-term adherence to the program was the strongest predictor of weight loss and weight loss maintenance.

In common language- these diets all work as long as the person eats less and keeps eating less over time. The most difficult part of the process is staying on the lower calorie diet over time. Studies showed that retention rates on the diet can be increased by contact with a weight loss program on a frequent and regular basis, especially if the program is offered without a fee.

Physical Activity

Most weight-loss programs have a physical activity component. The evidence does show that physical activity should be combined with reduction in calorie intake for weight loss. This is because the amount of exercise needed to lose weight, without reducing calories, is extreme. By combining exercise with lower calorie intake the most common detrimental outcomes of dieting – loss of lean tissue and lower resting metabolic rate– can be avoided. Exercise also helps by improving overall metabolic fitness. For many people it is easier to keep up a program in which they eat a bit less and exercise a bit more, than it is to engage in either single-type effort to eat little enough or exercise enough to bring about weight-loss. (Not to mention maintaining that restrictive a lifestyle over time) There is also some evidence that resistance training with a higher protein intake promotes the loss of fat, and the loss of weight while maintaining muscle mass. This may be particularly helpful in the case of elderly people who want to lose weight.

Behavioral

One of the most common problems faced in any weight loss program is ‘sticking to it’ over time. The longer a person maintains the program the longer it will work. As participation time increases people notice that weight loss is not as pronounced as it was at the beginning, and they begin to drop the activities that created the weight loss. Boredom with the diet and exercise program is stronger than rewards, behavioral cues and reminders, making behavioral interventions ineffective over time. A true internal commitment to lifestyle change that grows out of the person’s belief system and is maintained through a self-monitoring commitment is the most effective behavioral tool.

Pharmacotherapy

People report that they seek out drugs to help them lose weight to make it easier to stick to a diet.

Over the Counter Drugs

Drugs are readily available in the corner drug store, they are offered at a low cost and no prescription is needed for a wide array of over the counter diet pills. The most popular type of diet pill is an appetite suppressant. Over the Counter weight loss supplements promise to promote weight loss by increasing energy expenditure, reducing appetite, increasing fat oxidation, inhibiting the absorption of dietary fat, moderating carbohydrate metabolism, increasing fat excretion, increasing water elimination and enhancing mood. Since multiple metabolic pathways are targeted these weight loss supplements have been shown to increase the risk of adverse effects, even including death from cardiovascular complications. While diet pills are very popular among the general public, there is no evidence that over the counter drugs are effective for weight reduction or weight maintenance, nor safe for the consumer.

Prescription Drugs

People seeking anti-obesity prescription drugs report that they have an easier time maintaining weight after short term treatment with prescription medications. There are additional benefits of decreased blood pressure, lipid levels, and blood glucose levels along with an increase in insulin sensitivity and reduced risk of cardiovascular disease.  There are two primary types of prescription drugs used for treatment of obesity. These are: fat absorption inhibitors and anorexins which inhibit appetite. Both types are combined with standard weight-loss practices such as lower calorie intake, exercise and behavior modification.  Typically weight loss plateaus at about 6 months. The risks associated with weight loss medications include tolerance – leading to an increase level of medication needed for the same outcome; and addiction. Continuous monitoring by a medical professional is required.

Surgical

For those people who have been unable to achieve normal weight despite many strong attempts, Adjustable Gastric Banding (AGB) an improvement on the original Vertical Banded Gastroplasty (VBG) has been popular worldwide. In this approach a prosthetic band is surgically placed around the upper stomach so that small, frequent meals are eaten, resulting in weight loss. Slippage of the band, reflux esophagitis, and erosion into the stomach are the most common reasons for failure of this method. The Roux-en-y-gastric (RYGB) bariatric surgery method offers what current research reports as the best balance of effectiveness versus risk and is the most widely used surgery in the United States for what is considered those with morbid obesity.  Subsequent to this procedure most people lose 35-40% of their body weight and can maintain the weight loss for over 15 years. Post operative complications occur in about 10% of cases. Between the options of VBG and RYGB, RYG caused more weight loss and the weight loss was maintained in a higher number of cases.  Clinically significant levels of malabsorption have often been reported, but RYGB may enhance glucose disposal and contribute to a reversal of type 2 diabetes mellitus.

Genetic Considerations

Regardless of the approach taken to weight loss, there is a wide range of differences among persons’ response to the treatment which seems to suggest that there is a role played by genetics in weight gain, weight loss and weight maintenance.  Twin studies seem to support this finding as monozygotic twins usually have quite similar results from each type of intervention, while differing widely as pairs from the same treatment given to other sets of monozygotic twin pairs. While current advances in gene study have allowed researchers to study the role of genes in weight, published literature reports that the field has not advanced far enough for individual weight loss programs to be designed based upon genetics.

Conclusions and Recommendations

Despite the widespread interest among the population for a cure for obesity, obesity remains a “significant and challenging” clinical condition.  For many obese persons a weight loss of even just 5-10% will have significant health outcomes by preventing diabetes type 2, cardiovascular disease and loss of mobility. However, most people find even a relatively small weight loss is very hard to maintain over time.

The following recommendations based on published research can be made:

• Prevention of overweight is the most effective approach for healthy outcomes.
• Waist circumference divided by hip circumference is the best measurement of whether the person is overweight; followed by body mass index.  Weight alone is not a good predictor as it does not differentiate between muscle mass, fat and bone weights.
• Physical activity should be combined with restriction of calories to result in loss of fat with maintenance of lean mass and resting metabolism.
• A full lifestyle change with individual self-monitoring is the only known way to achieve and maintain healthy weight and metabolism.
• There are no effective over the counter dietary supplements for weight control. Prescription medications used under the care of a physician have been useful in the short term (6 months or less) but have been linked to addiction.
• Bariatric surgery is a somewhat risky but viable option for very obese persons for whom other approaches have failed.
• An emerging field of genetic studies may provide hope for preventing and curing obesity, in future years.

This report is based upon a study published in the Journal Nutrition in Clinical Practice.

Laddu, D., Dow, C., Hingle, M., Thomson, C., Going, S., (2011) A Review of Evidence-Based Strategies to Treat Obesity in Adults. Nutrition in Clinical Practice. 26:512-525