MYTH: Diets Make You Eat Less
Although dieters try to restrict their intake and there are some studies to show that they eat less than nondieters do, the evidence suggests that under many conditions, dieters typically eat the same or more than do nondieters. In one study researchers found that
the average daily caloric intake of dieters did not differ significantly from that of nondieters. Dieters in this study ate slightly more (on average 2234 cal/day) than did the nondieters (on average 2066 cal/day). The dieters also ate significantly more snacks and ate more frequently than did the nondieters. Many studies have found that across a variety of conditions, dieters typically eat more than do nondieters. It appears that maintenance of control of eating in dieters is rare. Numerous laboratory studies have revealed a variety of “diet disrupters” or triggers of overeating. These include anxiety, distress, depression, positive emotion, alcohol, actual or anticipated consumption of a “dietbreaking” food (e.g., a milkshake), or the mere exposure to the smell and thoughts of such foods. Many of the factors that trigger overeating in dieters typically inhibit eating in nondieters. For example, nondieters eat less than they would otherwise if they are anxious, distressed, or depressed. Research shows that people are good at maintaining their diets only as long as they are not exposed to any diet disrupting triggers. Unfortunately, in the real world the dieter is constantly subject to these, and is therefore likely to overeat frequently.
SelfPresentation or Cognitive Distortion
So why do people believe that dieters eat less than nondieters do? Well, presumably, the easiest way to lose weight is to eat less, and the expectation is that dieters should eat less because this is the best way to achieve their goal. Dieters, themselves, are motivated to think they are eating less or perhaps, to present themselves to others as eating minimally. In this way, they are succeeding at their socially acceptable goal: to be a good dieter. Research has shown that dieters significantly underreport what they have eaten—they tend to believe that they eaten much less than they actually have. In comparison, nondieters tend to be very accurate at reporting the amount they have eaten. This and similar findings may represent a cognitive distortion, functioning to protect the dieter’s selfesteem, which is more heavily dependent on weight and shape than that of the nondieter. It is also possible that the dieter is motivated to underreport consumption to others, as eating minimally is a socially desirable goal.
Adherence to Dietary Rules: When Do Dieters Eat Less?
When dieters come into the laboratory and are presented with an opportunity to eat as much as they like in the guise of a bogus “taste perception task,” they typically eat less than do nondieters. But, this is true only when no disinhibitory triggers are presented or manipulated. It would seem that dietary restraint is quite tenuous and that virtually anything can induce dieters to break their diets. A factor that induces “normal” eating (i.e., eating comparable to that of nondieters) and even decreased eating (i.e., eating less than nondieters) in dieters is an increase in the dieter’s selfawareness.
Increased selfawareness at either the private level (i.e., increased
consciousness about what they are eating) or at the public level (i.e., increased awareness that others are monitoring what they are eating) promotes adherence to the diet and suppresses eating in dieters. Given the laboratory research, one would expect to see that in naturalistic studies, dieters’ patterns of food intake would be characterized by alternating periods of restriction and overeating. Contrary to these expectations, several naturalistic investigations have found that dieters report eating less than nondieters. However, when we examine the methodology of these studies, a number of problems emerge. The majority of these studies must rely on the selfreport intake using dietary selfmonitoring forms or food diaries. The validity of a dieter’s selfreport of intake is questionable given the evidence that dieters to tend to underreport their food intake.
Selfmonitoring may also increase selfawareness, a factor shown to suppress eating in dieters.
If chronic dieters were truly eating less than nondieters, it would seem reasonable to expect that they would also weigh less. However, many studies consistently find that dieters weigh significantly more than do nondieters, and that they do not lose weight over time. This is further evidence that dieters may actually eat more than they report. Given the evidence that dieting leads to overeating or bingeing, it is possible that the consumption of such excess calories is manifested in an increased body weight in dieters—an unfortunate, and ironic, consequence of trying to lose weight. Many people who have dieted on and off for many years can look back at a picture of themselves when they first started to try and diet and wonder why they ever went on the diet in the first place, as over the years dieting has pushed up their weight.
What Prevents Dieters from Consistently Eating Less?
What prevents dieters from achieving their goal of consistent caloric restriction? One explanation for the association between dieting and overeating and for the proposal that dieting may lead to bingeing is that dieting involves substituting the cognitive regulation
of eating for physiological control, in order to override the body’s natural defence of weight. Cognitive regulation of eating is problematic because it is vulnerable to disruption by conflicting cognitions and emotional factors. In addition, ignoring the
physical sensations of hunger and satiety in favour of a cognitive diet program leaves one lacking a mechanism to stop intake if and when cognitive regulation fails. Other mechanisms of diet failure that have been proposed include pressures from physiological and psychological deprivation. Shortterm physiological deprivation from periods of restriction could increase vulnerability to episodes of overeating. For example, physiological indices suggest that dieters may be “hungrier” than nondieters. The most probable mechanism is a complex one that encompasses a number of factors, including cognitive restraint or psychological deprivation combined with cognitive, emotional and situational pressures. This conflict between physiological and psychological cues and internal and external forces in dieters is one specific example of a more general
phenomenon: the inhibition of a motivated behaviour typically leads to excess—the opposite of the intended suppression.
The NonDieting Alternative
In conclusion, dieting does not seem to produce reduced food intake. Dieters appear to be able to adhere to dietary rules for only a transitory period of time, at which point, inhibition is lifted by a dietbreaking trigger. This could be caused by almost anything—
from a fight with a friend, to being given a piece of birthday cake at a party. For the most part, dieters are not able to meet their goal of eating minimally. Alternatives to dieting have been described in various ways as “normal eating,” “antidieting,” and “undieting.” All of these approaches advocate several measures: (1) Giving up dieting and restriction of intake. These programs advocate “normalizing” eating with the goal of controlling eating by hunger and satiety, rather than cognitive and external factors. The elimination of the concept of “forbidden” foods also eliminates the psychological frustration associated with dieting. (2) Getting rid of the dieting mentality. If there is no diet, there is no opportunity for failing at it, and thus subsequent selfderogation is averted. (3) Working on accepting or tolerating the body at whatever its size. This frees up a lot of energy to work on other aspects of the self from which the
dieter can derive esteem and satisfaction and suggests a better area for making those New Year’s resolutions.