Anorexigenic Peptides

Effects of Cocaine- and Amphetamine-Regulated Transcript (CART) Cocaine- and amphetamine-regulated transcript (CART) is a recently discovered hypothalamic pept-ide which is regulated by leptin and is endowed with appetite-suppressing activity (69,70). In the rat, the CART gene encodes a peptide of either 129 or 116 amino acid residues (70). In contrast, only the short form of CART exists in humans (70). The mature peptide contains several potential cleavage sites and CART may be...

Leptin Deficiency And Appetite Control

It seems clear that for the majority of obese people, the OB protein (leptin) system is not a major cause of rapid or massive weight gain. However, for certain individuals very low levels of leptin (or the absence of leptin) may constitute a major risk factor. Recently a number of individuals have come to light. For example, two young cousins have been studied who displayed marked hyper-phagia from a very early age. This hyperphagia took the form of a constant hunger accompanied by food...

Efficacy Of Dietary Treatment

In the Clinical Guidelines, published by the National Institutes of Health and National Heart, Lung and Blood Institute 1998, an extensive analysis of the efficacy of various treatments for obesity is given (8). In this report, 86 randomized clinical trial publications were evaluated. These diets included ordinary low calorie diets, very low calorie diets (VLCDs), vegetarian, American Heart Association Guidelines and the National Cholesterol Education Program Step 1 Diet, as well as other low...

Weight Change After Smoking Cessation

Smoking cessation reliably produces weight gain in both women and men, although the magnitude of this gain, and the mechanisms involved are less clear (20,27). In the 1970s, a commonly reported but empirically unsupported estimate was that one-third of quitters gain weight, one-third remain the same, and one-third lose weight (28). Based on a review of 43 longitudinal studies, conducted primarily during the 1970s and 1980s, the average weight gain was estimated at 2.8 kg (0.8 to 8.2 kg) during...

Prevention And Treatment Of Maternal Obesity

It is often said that 'prevention is better than cure', but in the context of pregnancy, this cannot be taken as read. Because excessive gestational weight gain is probably the most important risk factor for maternal obesity, restricting the amount of weight that women gain should theoretically help to reduce the burden of obesity-related disease in women. However, restricting weight gain during pregnancy presents health care workers with a dilemma weight restriction may help to diminish the...

Implications For Obesity

The integrated impact of the differential regulation of macronutrient intake, digestion, absorption, storage and oxidation generally supports the hypothesis that dietary fat may be particularly associated with weight gain. This has been examined in a number of studies conducted over several days or weeks. Here the period of study must be related to the precision of the measurements of changes in macronutrient balance. Tightly controlled experimental studies performed in calorimeters, where...

Risk Factors For Type 2 Diabetes

Table 24.2 presents the known modifiable and non-modifiable risk factors or aetiological determinants associated with type 2 diabetes (27). The overall risk of type 2 diabetes must be assessed on the basis of all of these. Because of the additive effect of different risk factors and determinants, individuals with high levels of non-obesity risk may develop type 2 diabetes without becoming obese, while in other cases obesity alone may be sufficient to lead to diabetes. Generalized and central...

Dieting As A Change Behaviour

Dieting is part of a complex process of changing behaviour. Prochaska has described the various steps which a person takes in contemplating a possible change in behaviour before such change is actually implemented and hopefully also maintained during later phases (3). For such changes to take place, realistic goals must be available. Foster et al. have described that most patients joining an obesity clinic have goals which are clearly unrealistic and which may lead to frustration, early...

Defining Obesity in Children and Adolescents

The major factor limiting our understanding of the true extent of the childhood obesity problem is the lack of a standard population-level methodology for measuring overweight and obesity in children and adolescents. Presently a number of different methods or indices are in use with a variety of cut-off points for designating a child as obese. The US National Center for Health Statistics (NCHS) growth reference charts have been recommended by the WHO for international use since the late 1970s...

Altered Cortisol Metabolism In Obesity

Cortisol Metabolism in Primary Obesity Relatively small case-control studies, almost exclusively in women, showed that obesity, particularly of predominantly abdominal distribution, is associated with increased urinary free cortisol excretion (160-162). However, as detailed above, urinary free cortisol forms a very small fraction of total cortisol metabolite excretion. More convicingly, recent large studies confirm that total cortisol production rate is somewhat enhanced in obesity in men as...

Weight Differences Between Smokers And Nonsmokers

It is well established that middle-aged and older smokers weigh less than comparably aged non-smokers. In a review of 29 cross-sectional studies evaluating weight and smoking status, smokers weighed an average of 3.4 kg less than non-smokers (1,20,21). Weight differences between smokers and non-smokers tended to be greater for moderate smokers (compared to light or heavy smokers), older smokers, and women (20). Although most studies have been conducted in American populations, similar weight...

Obesity As A Genetic Disorder

Genetic and metabolic factors in the development of obesity have received increasing attention since the identification of the protein product of the ob gene leptin, and its receptor. Clearly there are cases among humans, as well as in strains of rodents, in which a single gene mutation has been identified as the direct and specific cause of obesity. That obesity is a genetic disorder is rarely disputed today. What remains under discussion is the relative magnitude of the contribution of genes...

Female Obesity

The prevalence of female obesity has increased steadily over the last 40 years in both the UK and the USA 1,2 . Even during the last decade, the prevalence of female obesity BMI gt 30 in Britain rose from 8 in 1980 to 12 in 1987 3 . This increase led the British government to identify 'the reduction of obesity' as one of its main targets for health improvement 4 , yet in spite of this initiative female obesity continues to rise and currently stands at 20 5 . Paradoxically, the increasing...

Antimigraine And Antihistaminergic Drugs

Weight gain is a common and early side effect of drugs such as sanomigran 69 and cyproheptadine 70 probably due to their combined antihista-minergic and serotonergic effect. The weight changes are, however, rather modest and the clinical importance of the problem is limited. Because to its ability to increase appetite attempts have been made to use cyproheptadine as a pharmacological support in the treatment of both anorexia nervosa 71 and cancer cachexia 72 , but so far without encouraging...

Risk Factors For Atherosclerotic Cardiovascular Disease In Obesity

Although obesity has been established as an independent risk factor for the development of atheros- Table 25.1 Ventricular dysfunction reported in severely obese patients 1. Impaired ventricular function 2. Abnormal response to exercise 3. Depressed contractility related to ventricular mass 5. Reduced ventricular wall and septal size clerotic cardiovascular disease ACVD , obese people often present well-recognized coronary risk factors such as hypertension, lipid abnormalities, and type 2...

Health Impact of Obesity in Childhood

Obese children and adolescents are at increased risk of developing a number of health problems. The most significant long-term consequence is the persistence of obesity and its associated health risks into adulthood. Some 30 of obese children become obese adults. This is more likely when the onset of obesity is in late childhood or adolescence and when the obesity is severe. Other obesity-related symptoms include psychosocial problems, raised blood pressure and serum triglycerides, abnormal...

Screening For Obesity To Prevent Type 2 Diabetes

The primary prevention of type 2 diabetes is an urgent issue and weight control in the population seems to be the most important part of the preventive process. The drastic predictions concerning the time trends of obesity and type 2 diabetes call urgently for research aimed at finding a solution or more probably several solutions to the problem. One approach could be a mass screening programme examining the whole population for body weight and offering obese individuals the opportunity to...

Key Factors Underlying the Increase in Childhood Obesity Rates

The fact that obesity is emerging as the most prevalent nutritional disease among children and adolescents in the developed world is hardly surprising. As outlined earlier, the highly technological societies of today have created an environment where it is increasingly convenient to remain sedentary whilst all forms of physical activity and active recreation are discouraged. Children are particularly susceptible to such changes as many of the decisions about diet and physical activity patterns...

Orexigenic Neuropeptides

Anorexigenic Neuropeptides

NPY is a 36 amino acid neuropeptide that is widely distributed in the brain. In the hypothalamus, it is synthesized in the arcuate nucleus and released in the paraventricular nucleus. It stimulates food intake by binding to Y1 and or Y5 receptor subtypes 12-14 . This increase in feeding can be observed upon infusing the peptide intracerebroventricularly i.c.v. in normal rats and is accompanied by a rapid, sustained and marked increase in body weight 15,16 . Central NPY infusion also stimulates...

Recent New Experience With Antiobesity Drugs

Orlistat Body Weight Eucaloric

Sibutramine Figure 31.1 is a centrally acting agent that dose-dependently inhibits serotonin and noradrenaline reuptake 49 . Sibutramine's action in inhibiting the reuptake of serotonin enhances satiety and thus decreases energy intake 50 . By inhibiting noradrenaline reuptake, sibutramine enhances sympathetic outflow, including to brown adipose tissue, leading to increased thermogenesis and thus increased energy expenditure. Figure 31.1 Structure of sibutramine and orlistat, two recent drugs...

Key Features And Patterns Of The Global Obesity Epidemic

Closer analysis of obesity prevalence and trend data from around the world reveals a number of interesting patterns and features. These include an increase in population mean BMI with socioeconomic transition, a tendency for urban populations to have higher rates of obesity than rural populations, a tendency for peak rates of obesity to be reached at an earlier age in the less developed and newly industrialized countries, and a tendency for women to have higher rates of obesity than men. These...

Growth Hormone And Abdominal Obesity

Secretion of Growth Hormone in Abdominal Obesity With increased adiposity, GH secretion is blunted with a decrease in the mass of GH secreted per burst but without any major impact on GH secretory burst frequency 69 . Moreover, the metabolic clearance rate of GH is accelerated 70 . The serum insulin-like growth factor I IGF-I concentration is primarily GH dependent and influences GH secretion though a negative feedback system 71 . The serum levels of IGF-I are inversely related to the...

Pathology Of Cortisol Metabolism

Much of what we have learnt of the physiology of cortisol metabolism has been inferred from observations of the consequences of pathology. In this section, we review these pathological clinical syndromes and experimental models. Measurement of Cortisol Metabolism in Humans The established technique for assessing different routes of cortisol metabolism in humans is to measure the principal metabolites of cortisol in urine, using gas chromatography-mass spectrometry GCMS 120,121 . Examples of...

Measuring Central Obesity

For a comprehensive estimate of weight-related health risk it is also desirable to assess the extent of intra-abdominal or 'central' fat accumulation. This can be done by simple and convenient measures such as the waist circumference or waist-to-hip ratio. Changes in these measures tend to reflect changes in risk factors for cardiovascular disease and other forms of chronic illness. Some experts Table 1.2 Sex-specific waist circumference measurements for identification of individuals at...

Physiology Of Cortisol Metabolism

Cortisol Metabolism Hsd

The principal metabolites of cortisol are shown in Figure 18.2. The enzymes directly metabolizing cor tisol include the A-ring reductases 5a- and 5P-reductases , 6 -hydroxylase, 20-reductase, and 11 -hydroxysteroid dehydrogenases. In rats and mice, which lack 17-hydroxylase in their adrenal cortex, the principal glucocorticoid is corticosterone, which is subject to analogous metabolism. 11 P-Hydroxysteroid Dehydrogenases 1ip-HSDs These enzymes catalyse the interconversion of cortisol or...

Inconsistent Trends In Obesity And Fat Intake

Fat Intake And Obesity Trend

Although trends in fat intake have been found to correlate closely with trends in cardiovascular disease, several studies have demonstrated that obesity is increasing at the same time that fat intake is decreasing 7 . In fact, some of the countries that have experienced a substantial decrease in fat intake have noted the most dramatic increases in obesity prevalences. In Finland, for instance, prevalence of obesity rose from 10 to 14 in men and from 10 to 11 in women between the late 1970s and...

Dietary And Behavioural Principles In The Treatment Of Obesity. International Monitor On Eating Patterns And Weight

Department of Agriculture, Agricultural Research Service. Data tables results from USDA's 1995 continuing survey CSFI DHKS 1995. Riverdale, Md. Food Surveys Research Group, 1995 CD-ROM . 2. Johansson L, Drevon CA, Bjorneboe GEA. The Norwegian diet during the last hundred years in relation to coronary heart disease. Eur J Clin Nutr 1996 50 277 283. 3. Fogelholm M, Mannisto S, Vartiainen E, Pietinen P. Determinants of energy balance and overweight in Finland 1982 and 1992. Int J Obes 1996 20...

The Psychobiological System Of Appetite Control

Appetite Diagram

It is now accepted that the control of appetite is based on a network of interactions forming part of a psychobiological system. The system can be conceptualized on three levels Figure 8.1 . These are the levels of psychological events hunger perception, cravings, hedonic sensations and behavioural operations meals, snacks, energy and macronut-rient intakes the level of peripheral physiology and metabolic events and the level of neurotransmitter and metabolic interactions in the brain 2 ....

Methods For Anthropometric Measurements

Mri Abdominal Intra Abdominal Fat

Weight is measured by digital scales or beam balance to the nearest 100 g. For those unable to stand, electronic chair scales Weighcare C, Marsden Ltd, London are available. For field work, portable scales are used. Equipment is calibrated regularly by standard weights 4 x 10 kg and 8 x 10 kg , and the results of test weighing recorded in a book. Subjects are weighed in light clothing, fasting and with an empty bladder, preferably at the same time of day. Height is measured by stadiometer to...

The Scale of the Childhood Obesity Problem

Despite the lack of agreement over childhood obesity classification, there is ample evidence to illustrate the scale of the problem across the world. Using the existing WHO standards, the 1998 World Health Report indicated that about 22 mil- OBESITY AS A GLOBAL PROBLEM Table 1.9 Prevalence of overweight in 6- to 8-year-old children USA China Russia South Africa Brazil 1988-1991 1993 1994-1995 1994 1989 Girls 24.2 12.2 17.8 20.3 10.5 Boys 21.3 14.1 25.6 25.0 12.8 Defined as BMI higher than the...