140 Dieting
control groups, since changes of the kind identified could have resulted from
participation in research on eating. However both studies suggest that changes
in cognitions and self-control can be identified, which might well exacerbate
eating problems. In addition, a feature common to the studies by Keys et al.
(1950), Warren and Cooper (1988), and Polivy et al. (1994) is that the food
restriction was externally imposed, which is different from the self-imposed
food restriction characteristic of dieters. The restriction of food intake was
part of the experiment and therefore not entirely a product of the subject’s
motivation for weight loss. It is possible that the impact of a self-imposed
restrictive regimen would be different. To explore this possibility, Ogden
(1995) monitored the effects of self-imposed dieting over a 6-week period
in 23 dieters who completed rating scales of mood and cognitive and motiva-
tional states three times a week, and profile questionnaires at the beginning
and end of the 6-week period of caloric restriction. A control group of 18
nondieters was also assessed for a comparative period. The results showed
some differential changes over the period of the diet, with the dieters show-
ing increases in both depression and loss of control, a decrease in hunger,
and a temporary increase in the preoccupation with food compared to the
nondieters. These results suggest that dieting can have several negative
consequences which may then trigger subsequent overeating.
The extensive research into obesity treatment is also relevant to the
association between dieting and mood. One perspective has been that obese
people are depressed as a direct result of being overweight, and that
weight loss decreases the overall experience of depression. This has been
supported by several studies using a range of methods (e.g., Shipman and
Plesset, 1963; Crisp et al., 1980; Wing et al., 1984). In contrast, it has been
suggested that obesity and overeating are a defense against depression, and
that reducing food intake should result in a lowering of mood (Kornhaber,
1970). Wadden, Stunkard, and Smoller (1986) evaluated the emotional
consequences of dieting in a group of obese patients undergoing behavior
therapy. The results showed that the subjects reported an increase in
negative mood as a response to the treatment regimen. However, as with
studies assessing caloric restriction in the nonobese, evaluating the results
from the behavioral treatment of the obese is also limited by the absence
of a nondieting control group.
Not all research, however, indicates that dieting results in lowered
mood. Polivy and Herman (1999b) questioned why dieters continue to diet
when their diets fail, when they show no weight loss, and when dieting has
so many negative consequences, and argued that dieters show the “false