Obesity and Depression
Obesity is increasingly a problem in the United States. Approximately one-third of the American population is obese, meaning someone weighs more than 20% above the ideal weight for their height. The number of overweight Americans has risen steadily during the past decade, including the number of seriously obese adults and overweight children.
The obese are often unhappy about their weight and may also be clinically depressed, prompting a great deal of study and speculation about the connection between obesity and depression. Does overeating and overweight lead to depression or does depression lead to overeating and overweight? The relationship is probably circular, each one relating to the other.
The research on obesity and its negative psychological effects generally falls into two categories. The first examines the psychosocial reasons for depression in the obese; the second looks for neurochemical or genetic connections in the body that link obesity with depression.
The psychological approach
Being overweight is a tremendous source of dissatisfaction, depression and frustration for Americans. A survey published in Psychology Today found that weight was so important that 24% of women and 17% of men would give up more than three years of life in exchange for being thinner. Ironically, some obese individuals are already shortening their lives because of the adverse effects of excess body weight.
Scientists have proposed many possible causes for the depression that obese people suffer, including society’s negative attitudes toward overweight people, negative body image, negative stereotypes, race, education, dieting and the effect of poor physical health on mood.
Society's negative response
The most common assumption about the link between depression and obesity is that being overweight is viewed negatively by our society and this is internalized as self-rejection. Clearly, though, not all of the obese are depressed or even unhappy with their weight. Women especially are prone to being unhappy about their weight, while men and older people are much less disturbed by it. Heavy women are likely to report varying degrees of distress, ranging from feeling unattractive to feeling undesirable, rejected and a failure.
Body image, feelings and attitudes about one's body have been found to affect a person's mental condition. Negative body image is linked to depression, low self-esteem, lowered sexual drive and poor health habits. Not only do most obese individuals feel ostracized by society, they also report mistreatment by the medical community that claims to be helping them. They feel their problem is considered less acceptable than almost any other medical condition.
Obesity carries an undeserved social stigma. The obese are stereotyped as stupid and lazy. A study that followed teens into adulthood found that those who were obese achieved less education and lower income and that fewer of them married. Many obese individuals have been teased and rejected from childhood on. A study of obesity and social class found that children as young as 7 years old negatively stereotyped the obese and that this prejudice was more extreme in children of higher socioeconomic status.
Race, socioeconomic status and education
Because eating disorders, which include anorexia and bulimia, appear to afflict Caucasians more frequently than African Americans, researchers have questioned whether body image dissatisfaction is linked to race. African Americans report being less concerned about weight and more accepting of their size, whether or not they are overweight. Some experts, however, theorize that, rather than race, socioeconomic status is a better predictor of this link. The wealthier the individuals, the more they feel stigmatized by being overweight.
A study comparing level of education and depression among the overweight claimed that being overweight was so widespread that it was not stigmatizing to most people. For well-educated women, though, being overweight is more uncommon and therefore, more distressing.
Some experts have proposed that being obese is not what makes people depressed, rather their constant efforts to diet are the source of their depression. The scientific literature shows that low-calorie diets are associated with depression. The deprivation involved in low-calorie diets, the preoccupation with food that accompanies dieting, dieting’s interference with normal social activities, and the guilt of failing to stick with a diet and then regaining the lost weight are all thought to contribute to depression.
It is known that patients suffering ill health report greater depression. Being overweight is a risk factor for high blood pressure, heart disease, diabetes, joint pain and limited physical functioning. Thus, the obese are frequently in poor health, and it is hypothesized that this may contribute to depression in obese individuals. In addition, the obese are more sedentary than normal-weight individuals, thereby denying themselves the psychological benefits of regular exercise. Fitness is associated with better physical and mental health and improved self-confidence, self-image and self-control.
A study of the elderly (who are more likely to be in poor health) contradicts the assumed association between obesity and depression. It found that older men who were obese were significantly less depressed than non-obese men. Because depressed older men have diminished appetite and tend to lose weight, depression tends more to be associated with low weight rather than obesity in this age group. In women, depression remains linked to obesity, but for both men and women over 70, ill health and greater physical limitation are generally associated with weight loss, not weight gain.
Scientists studying obese mice electrified the world when they found an abnormal gene that they named "ob." The gene was abnormal because it lacked leptin, a hormone produced by fat cells that is supposed to suppress appetite. When the scientists added leptin to the gene, the obese mice rapidly lost weight. Unfortunately, leptin does not work the same way in humans. This led scientists to examine the gene further. They found that variations of the "ob" gene were related to anxiety and depression. Some researchers think the gene may activate a neurotransmitter (a brain chemical that transmits nerve impulses) and that this has an effect on behavior, as well as on appetite and metabolism.
Understanding carbohydrate craving
Some obese people overeat and crave carbohydrates, while avoiding protein-rich foods. At mealtimes, they eat normally, but, in the late afternoon and evening, they are driven to snack, increasing their caloric intake by as much as 50%. It appears that as many as two-thirds of all obese people are carbohydrate cravers, though not all carbohydrate cravers are obese.
Obese carbohydrate cravers often score high on tests for depression. When they were asked why they eat so much food, knowing they will gain weight, they say it is rarely connected to hunger or taste. They believe these foods help them feel calm and reduce their anxiety. While some carbohydrate cravers feel better after a carbohydrate-rich meal or snack, others feel guilty and worry about their weight and health.
One theory supported by research suggests the brain chemical serotonin may play a key role in carbohydrate cravings. The amino acid, tryptophan, increases in the blood when carbohydrates are eaten. Carbohydrates stimulate the secretion of insulin, which speeds the uptake of tryptophan into the central nervous system where it is converted into serotonin in the brain. Serotonin, in turn, regulates mood and sleepiness. Patients with carbohydrate craving are thought to have a faulty serotonin feedback mechanism that neglects to tell the body to stop craving carbohydrates. When the feedback mechanism is disturbed, the brain fails to respond when carbohydrates are eaten and the desire for them persists.
This research led to the development of the diet drugs Redux and fenfluramine, both of which increase serotonin levels in the brain. Initially, the medication appeared to be a success since the pills helped suppress carbohydrate snacking and helped some overweight people to lose weight. But after millions had taken these medicines, serious side effects were discovered and they were taken off the market.
A recent study indicates that people who crave carbohydrate might be able to train themselves to cut carbs and boost protein in their diets. People in the study who were given a protein-rich meal consumed fewer calories than those eating a carbohydrate-rich meal. They tended to binge less, too. Further research may clarify the mechanisms behind craving, appetite, diet and mood.
Making health the first priority
Until scientists can unravel the puzzle of obesity and depression, a helpful approach, especially for those who are unable or unwilling to lose weight, is to encourage patients to accept their bodies and to focus instead on healthy living and exercise rather than on weight per se. Significantly obese individuals who have been encouraged to stop dieting and to accept their bodies have achieved measurable improvements in mood and self-esteem, even though some have gained rather than lost weight.
Physicians agree that obesity does heighten the risk of heart disease, hypertension, musculoskeletal problems and diabetes. Extreme or morbid obesity, which some define as being 100 pounds or more above ideal body weight, carries dramatically increased risks of serious illness and early death. Even modest weight loss can improve these conditions. There are increasing numbers of overweight people who are active and healthy and who enjoy their lives, even though they do not fit the American ideal in body size.
Many health professionals are beginning to incorporate this new attitude in focusing on exercise, improving mental attitude and teaching healthy eating habits.