There are conflicting views on the value of weight-loss diets. Some believe that if individuals have enough willpower to stick with a diet, they can lose an unlimited amount of weight. Others believe that weight loss attempts are rarely successful and weight regain invariably occurs.
There are many questions to ask when evaluating “does dieting work?”
- Do dieters continue to lose weight?
- Does some of the lost weight return?
- Do some dieters gain back more weight than they lost?
In one study, women participating in a weight-loss program reported their goal weight as an average 32% reduction in body weight. After 48 weeks of treatment and an average loss of 35 lbs., 47% of women did not achieve weight loss they associated with success. Thus, what are achievable goals?
What is occurring in the USA?
In the USA, obesity has increased dramatically. The number of adults trying to lose weight by dieting and the amount of money spent on weight-loss has also increased. Using the most recent data from the CDC’s National Center for Health Statistics [NCHS], more than one-third of U.S. adults (34.9%) were obese in 2011 to 2012. Approximately half of all adults are trying to control weight, with about one-third of men and nearly one-half of women trying to lose weight. Additionally, we spend approximately $50 billion per year on weight-loss efforts.
Why should I lose weight?
From a medical perspective, preventing metabolic disease, such as hypertension, type 2 diabetes, coronary artery disease, and dementia, is the single most important health issue today. Obesity is associated with all of these common chronic diseases.
Meanwhile, sustained modest weight loss is associated with health improvements:
- Decreased risk for type 2 diabetes
- Reductions in blood pressure
- Improved lipid profiles
Health improvements begin to appear with weight loss of 5-7% of body weight. In 1998, the National Institutes of Health recommended weight loss for persons with a BMI (body mass index) of 30 or more and for persons with a body mass index between 25 and 29.9 with two or more risk factors (i.e. hypertension, type 2 diabetes, abnormal lipids, coronary artery disease). BMI is a person’s weight in kilograms (kg) divided by his or her height in meters squared. BMI is useful in population studies because it is easy to obtain and, in general, is a useful measure of health and longevity. It does not distinguish body fat weight from muscle or bone weight.
What are the results of most diets?
HealthPartners Health Behavior Group in collaboration with Kaiser Permanente’s Care Management Institute completed a review of long-term weight-loss interventions. Weight-loss studies reviewed were categorized into eight types of interventions: advice alone, diet alone, diet and exercise, exercise alone, meal replacements, very-low-energy diets, and weight-loss medications. The purpose of the systematic review was to answer the question raised above: Do diets work?
In studies with a minimum follow-up of 12 months, mean weight loss of approximately 11 lbs. to 18 lbs. (5-9%) was observed during the first six months with a reduced-calorie diet and/or weight-loss medications. However, a weight-loss plateau usually occurred at approximately 6 months. In weight loss studies involving low-calorie diets extending to 48 months, a mean loss of 6 lbs. to 13 lbs. (3-6%) occurred and was maintained. In studies with advice only and exercise alone, groups experienced minimal weight loss. In summary, weight loss interventions utilizing a reduced calorie diet and exercise are associated with the best moderate weight loss outcome at six months.
Weight regain after a diet is your body’s evolved response to starvation. Additionally, your genes are involved in regulating your weight. To compare the effect of genetics versus the environment on the body-mass index, A.J. Stunkard studied samples of identical and fraternal twins, reared apart or reared together in Sweden. Stunkard concluded that genetic influences on body mass index (BMI) were more important than the childhood environments.
“Genetic factors appear to be major determinants of the body mass index in Western society, and they may account for as much as 70% of the variance.”
If the environment has no influence, then external factors such as culture, exercise, and dietary choices have no influence on your BMI. This sounds counterintuitive but this is part of the rationale of those who recommend “no diets”.
The above research is correct; the interpretation, however, is incorrect. The BMI has only two components: height and weight. Height in western societies is approximately 100% determined by genetics. With BMI, 70% is determined by genetics, suggesting that 40% of your weight is determined by genetics. Thus, environment has a major role in determining your weight and diet is very important.
Diet and exercise together
The combination of diet and exercise together will achieve greater weight lossand will allow longer maintenance of weight loss than either intervention alone. Exercise can include many different activities, but, in general, can be divided into two main categories: cardiovascular or endurance exercise and resistance training.
Why do diets fail?
The main reason diets fail is that we are addicted to eating unhealthy food and modern society misinforms us. Sugar can be a substance of abuse and lead to a natural form of addiction. Food addiction occurs because the brain pathways that evolved to respond to natural rewards are also activated by addictive drugs and by sugar. Sugar is noteworthy as a substance that releases opioids and dopamine and has addictive potential. The four components of addiction are:
Each can be demonstrated to be present with sugar bingeing. These behaviors are related to the neurochemical changes in the brain that occur with addictive drugs and with sugar.
The obesity epidemic in this country has been aided by the low cost of high glucose-containing carbohydrates. These foods are inexpensive because their production and storage are subsidized by the U.S. government in the Farm Bill. For the past 50 years, U.S. farm policy has been directed towards driving down the price of farmed storable carbohydrates.
At the same time, the cost of growing fruits and vegetables has increased, as has their retail price. Low costs incentivize the food industry to use more of these unhealthy commodities. High-fructose corn syrup is now commonly added to many processed foods.
In summary, the food industry has a huge financial incentive to make food with high-glycemic carbohydrates (sugars). They also use sophisticated marketing tools. “Marketing” is defined as “whatever it takes to make you buy a specific product.” One of the most useful marketing techniques is to aim marketing messages at children, who then nag their parents to buy this or that product; then, the child may continue to buy that product well into adulthood. The food industry spends over $1.6 billion dollars marketing food to children. Most of these products are processed foods high in calories and addicting sugar.