Obesity Treatment 189evaluated data from the Framingham Heart Study and assessed the effects
of weight variability in 5,127 men and women over 32 years. The results
suggested that weight variability was associated with all-cause mortality,
and with mortality and morbidity from coronary heart disease, in both sexes.
Likewise, research on rats suggests that repeated attempts at weight loss
followed by weight regain result in further weight loss becoming increas-
ingly difficult due to a decreased metabolic rate and an increase in the per-
centage body fat (Brownell, Greenwood et al., 1986). Lissner and Brownell
(1992) reviewed the literature on weight fluctuations and concluded that
there was consistent evidence for an association between weight fluctua-
tion and all-cause mortality, particularly coronary mortality. Therefore,
as dieting in the nonobese can cause weight fluctuation (Heatherton et al.,
1991; see chapter 7 above), yo-yo dieting in the obese may similarly cause
weight cycling and be more detrimental to physical health than remaining
statically obese. The research into the relationship between weight variability
and health, however, remains controversial, as some work has found no
association between these factors (Muls et al., 1995). In addition, it has been
argued that weight fluctuation may simply be a proxy measure for diseases
such as irritable bowel syndrome, tuberculosis, coronary heart disease, or
diabetes (Muls et al., 1995). From this perspective weight fluctuations are
seen as a marker of other causes of mortality rather than the cause per se.
The debate is still in its preliminary stages, but the focus has shifted from
weight per se as a predictor of health status to accepting a role for weight
variability regardless of baseline weight.
Restraint theory suggests that dieting may have negative consequences
(see chapter 7), and yet most obesity treatments recommend dieting as a
solution. This paradox can be summarized as follows:
- Obesity treatment aims to reduce food intake, but restrained eating can
promote overeating. - The obese may suffer psychologically from the social pressures to be
thin (although evidence of psychological problems in the nondieting
obese is scarce), but failed attempts to diet may leave them depressed,
feeling a failure and out of control, which is also detrimental to health. - Weighing is central to most treatment of obesity but may not be the
benign intervention it is considered to be, contributing to lowered
mood and self-esteem and changes in food intake. - Obesity is a physical health risk, but restrained eating may promote weight
cycling.