Excessive food aversion, compulsive exercise and decreased height gain due to fear of obesity in a prepubertal girl

Effects of conditioned food aversions on nutritional behavior in humans

Conditioned food aversion (CFA) and taste aversion (CTA) are widely occurring phenomena mediating rejection of solids or liquids, the ingestion of which has induced the onset of post-ingestional malaise. It is a powerful and durable imprint learning that may influence food choice and intake in all animals, including humans. For ethical reasons, CTA has been extensively investigated in a wide variety of laboratory animal's species but only incidentally in humans. Nevertheless, convincing evidence has been provided that CFA and CTA learning are possible in a wide range of human subjects. The results in humans may have some limitations in accuracy since data are sparse, sometimes indirect, and poorly controlled. There is only limited information on the extent of CFA in the elderly since most studies have employed questionnaire and/or interview methods on young people (i.e. college students). The present review evaluates the literature derived both from laboratory animals and humans. In the first instance, the salient features of food and taste aversion learning and the neural mechanisms involved in this learning behavior will be examined. Then, the problems encountered when trying to assess the role of learned food and taste aversions in the nutritional status of healthy as well as sick young or elderly people will be considered. In particular, the importance of CFA on the nutritional status of cancer patients and treatment of alcoholism will be examined. It is concluded that the data are compelling enough to warrant further research and, some indications and recommendations are suggested.

Metabolic bioenergy homeostatic disruption: a cause of anorexia nervosa

We believe anorexia nervosa is the result of a disruption in bioenergy homeostasis induced by lipid dysregulation. This disruption has two major determinants: (1) a biological predisposition to primary multihormonal disharmony linked to post-pubertal growth and development; and (2) an acquired abnormal lipid-induced loop operation precipitated by inappropriate diet. We present a step-by-step model describing the cascade of disorders that culminates in anorexia nervosa: defective digestion and absorption of essential fatty acids; diversion of lipids from adipose cells into bloodstream; defective carbohydrate and lipid metabolism which modifies the blood brain barrier; neuroendocrine membrane alteration causing severe endocrine impairment; changes in the negative feedback mechanism which escalate the body's use of bioenergy; derangement of the appetite center which causes a constant sensation of satiety; replacement of the correct body image with the premorbid one that encourages poor judgement concerning food intake and self-support. The loop-like nature of this mechanism perpetuates the disease.

Eating disorders in the Far East

OBJECTIVE

To investigate eating disorders (EDs) prevalence rates among Asian populations and identify characteristics that distinguish them from their Western counterparts.

METHOD

Potential references were identified through an English-language literature search using Medline, Psychinfo, Dissertation Abstracts (1966 to 1999) and through extensive manual searching of textbooks, reviews and reference lists.

RESULTS

The majority of studies related to EDs were conducted in Japan and China and a few were conducted in Singapore, Malaysia, Taiwan, and Korea whereas there was none in the Philippines, Laos, Vietnam, Cambodia, Myanmar, Indonesia and Thailand. Prevalence rates in Japan range from 0.025 to 0.030% for anorexia nervosa (AN) and from 1.9 to 2.9% for bulimia nervosa (BN). Community studies in China have found the AN prevalence to be 0.01% and BN rates ranging from 0.5% to 1.3%. These rates are lower than ED rates in the West (particularly the U.S. and Britain). Body dissatisfaction (BD) and dieting rates, however, were similar to those in the West. BD rates ranged from 68% (Taiwan) to 81% (Korea) and dieting rates ranged from 34% (Taiwan) to 68% (Japan). Sociocultural and developmental risk factors were relevant to this population.

CONCLUSIONS

EDs in Asian populations have received little attention because they have been predominantly viewed as associated with Western culture. Classified by many as a "culture-bound syndrome" of the West, they may really be a culture-change syndrome.

Temporal course of the development of obesity in Japanese school children: a cohort study based on the Keio Study

OBJECTIVE

To demonstrate the temporal course of obesity development in Japanese school children by conducting a school-site cohort study over 12 years.

METHODS

From 1981 to 1984, height and weight of 479 subjects (343 boys and 136 girls) were measured every year from entrance into primary school until graduation from high school in Tokyo. Obese children were defined as those with a body mass index (BMI) at or above the age-sex-specific standard value, derived from Japanese nationwide data.

RESULTS

Approximately 50% of the children who were obese in the primary school period were obese at age 17. Likewise, 40% who were obese in the junior high school period and 70% who were obese in the high school period were obese at age 17. Among 44 children who were obese at age 17, 14 showed tracking of obesity from the preschool period, 14 showed tracking from ages 7 to 11 years, 10 showed tracking from the junior high school period, and 6 showed tracking from the high school period.

CONCLUSIONS

Among children who were obese at age 17, most tracked from the primary school age or earlier. The earlier the tracking commenced, the greater the BMI at age 17. This indicates the importance of conducting health education for school children at an early age.