The mechanisms that balance food intake and energy expenditure determine who will be obese and who will be lean. One of the molecules that regulates energy balance in the mouse is the obese (ob) gene. Mutation of ob results in profound obesity and type II diabetes as part of a syndrome that resembles morbid obesity in humans. The ob gene product may function as part of a signalling pathway from adipose tissue that acts to regulate the size of the body fat depot.

Positional cloning of the mouse obese gene and its human homologue

The European Working Group on Sarcopenia in Older People (EWGSOP) developed a practical clinical definition and consensus diagnostic criteria for age-related sarcopenia. EWGSOP included representatives from four participant organisations, i.e. the European Geriatric Medicine Society, the European Society for Clinical Nutrition and Metabolism, the International Association of Gerontology and Geriatrics-European Region and the International Association of Nutrition and Aging. These organisations endorsed the findings in the final document. The group met and addressed the following questions, using the medical literature to build evidence-based answers: (i) What is sarcopenia? (ii) What parameters define sarcopenia? (iii) What variables reflect these parameters, and what measurement tools and cut-off points can be used? (iv) How does sarcopenia relate to cachexia, frailty and sarcopenic obesity? For the diagnosis of sarcopenia, EWGSOP recommends using the presence of both low muscle mass + low muscle function (strength or performance). EWGSOP variously applies these characteristics to further define conceptual stages as 'presarcopenia', 'sarcopenia' and 'severe sarcopenia'. EWGSOP reviewed a wide range of tools that can be used to measure the specific variables of muscle mass, muscle strength and physical performance. Our paper summarises currently available data defining sarcopenia cut-off points by age and gender; suggests an algorithm for sarcopenia case finding in older individuals based on measurements of gait speed, grip strength and muscle mass; and presents a list of suggested primary and secondary outcome domains for research. Once an operational definition of sarcopenia is adopted and included in the mainstream of comprehensive geriatric assessment, the next steps are to define the natural course of sarcopenia and to develop and define effective treatment.

/pdf/sarcopenia-european-consensus-on-definition-and-diagnosis-2axty2moc3.pdf

Sarcopenia: European consensus on definition and diagnosis Report of the European Working Group on Sarcopenia in Older People

Summary: In 1995 the American College of Sports Medicine and the Centers for Disease Control and Prevention published national guidelines on Physical Activity and Public Health. The Committee on Exercise and Cardiac Rehabilitation of the American Heart Association endorsed and supported these recommendations. The purpose of the present report is to update and clarify the 1995 recommendations on the types and amounts of physical activity needed by healthy adults to improve and maintain health. Development of this document was by an expert panel of scientists, including physicians, epidemiologists, exercise scientists, and public health specialists. This panel reviewed advances in pertinent physiologic, epidemiologic, and clinical scientific data, including primary research articles and reviews published since the original recommendation was issued in 1995. Issues considered by the panel included new scientific evidence relating physical activity to health, physical activity recommendations by various organizations in the interim, and communications issues. Key points related to updating the physical activity recommendation were outlined and writing groups were formed. A draft manuscript was prepared and circulated for review to the expert panel as well as to outside experts. Comments were integrated into the final recommendation.

Primary Recommendation: To promote and maintain health, all healthy adults aged 18 to 65 yr need moderate-intensity aerobic (endurance) physical activity for a minimum of 30 min on five days each week or vigorous-intensity aerobic physical activity for a minimum of 20 min on three days each week. [I (A)] Combinations of moderate- and vigorous-intensity activity can be performed to meet this recommendation. [IIa (B)] For example, a person can meet the recommendation by walking briskly for 30 min twice during the week and then jogging for 20 min on two other days. Moderate-intensity aerobic activity, which is generally equivalent to a brisk walk and noticeably accelerates the heart rate, can be accumulated toward the 30-min minimum by performing bouts each lasting 10 or more minutes. [I (B)] Vigorous-intensity activity is exemplified by jogging, and causes rapid breathing and a substantial increase in heart rate. In addition, every adult should perform activities that maintain or increase muscular strength and endurance a minimum of two days each week. [IIa (A)] Because of the dose-response relation between physical activity and health, persons who wish to further improve their personal fitness, reduce their risk for chronic diseases and disabilities or prevent unhealthy weight gain may benefit by exceeding the minimum recommended amounts of physical activity. [I (A)]

Physical activity and public health: updated recommendation for adults from the American College of Sports Medicine and the American Heart Association.

Ten per cent of the world’s school-aged children are estimated to be carrying excess body fat (Fig. 1), with an increased risk for developing chronic disease. Of these overweight children, a quarter are obese, with a significant likelihood of some having multiple risk factors for type 2 diabetes, heart disease and a variety of other co-morbidities before or during early adulthood. The prevalence of overweight is dramatically higher in economically developed regions, but is rising significantly in most parts of the world. In many countries the problem of childhood obesity is worsening at a dramatic rate. Surveys during the 1990s show that in Brazil and the USA, an additional 0.5% of the entire child population became overweight each year. In Canada, Australia and parts of Europe the rates were higher, with an additional 1% of all children becoming overweight each year. The burden upon the health services cannot yet be estimated. Although childhood obesity brings a number of additional problems in its train – hyperinsulinaemia, poor glucose tolerance and a raised risk of type 2 diabetes, hypertension, sleep apnoea, social exclusion and depression – the greatest health problems will be seen in the next generation of adults as the present childhood obesity epidemic passes through to adulthood. Greatly increased rates of heart disease, diabetes, certain cancers, gall bladder disease, osteoarthritis, endocrine disorders and other obesityrelated conditions will be found in young adult populations, and their need for medical treatment may last for their remaining life-times. The costs to the health services, the losses to society and the burdens carried by the individuals involved will be great. The present report has been written to focus attention on the issue and to urge policy-makers to consider taking action before it is too late. Specifically, the report:

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1467-789X.2004.00133.x

Obesity in children and young people: a crisis in public health.

Targeted disruption of the melanocortin-4 receptor results in obesity in mice

The Merriam-Webster dictionary defines hunger as (1) a craving for food, and (2) any strong craving. Appetite is defined as the natural desire for satisfying some want or need, as of food. Other definitions have introduced emphasis on this or that component. Carlson,’ for example, has defined hunger as “a more or less uncomfortable feeling of pressure and pain referred to the region of the stomach”; Grossman and Stein: in an excellent article on hunger feelings following insulin and their persistence after vagotomy, have distinguished between the sensation of being “hungry all over” and epigastric pangs. Other authors have emphasized differences in psychic associations, as well as in intensity, between appetite and hunger. All these considerations should make it clear that hunger and appetite are generally understood to be sensations or feelings that, as such, are not properly amenable to regulation. The sensory meaning has been so generally accepted that, desirable though it may be to reject it, as suggested by Doctor Hollander, it seems a little late in the day to do so. It is even diflicult to record the appearance of these sensations and, a fortiori, their intensity, except through a behavioristic approach. As all of us have known empirically since childhood and as can be clearly evidenced in the laboratory, a multiplicity of factors, emotions, urges, environmental temperature, necessity for exercise, will interfere to modify the tendency to partake of food. Often, the course of action in time of these factors is complex: acute exposure to cold will inhibit tendency to eat in a first phase, yet increase it later. When dealing with a problem which can be attacked only behavioristically and which depends on a multiplicity of variables, the only systematic approach that I know of is the statistical method of Skinner, who studied the frequency or probability of responses to this or that stimulus. With the collaboration of Anliker, an experimental psychologist versed in the “Skinner box” techniques (as well as in electronics and recording techniques), we have recently embarked on the study of the probability of response to exposure to food and on the frequency of work for food of normal mice, as well as of littermates with the hereditary obese hyperglycemic syndrome, goldthioglucose obesity, and hypothalamic obesity. This study will enable us, we hope, to obtain analysis of correlations of response to various physiologic stimuli, as well as an exploration of how much conditioning can be introduced in these responses. Results, however, are too preliminary to warrant a report a t this date. Even then, of course, they will not deal with a regulation, but only with a pattern of feeding.

Regulation of energy intake and the body weight: the glucostatic theory and the lipostatic hypothesis.

From the Chicago MeetingsSarcopenia

Hypoferraemia in obese adolescents.

I T IS GENERALLY assumed that the relationship of food intake to exercise is one of direct proportionality above the basal level corresponding to inactivity. It is the purpose of the first part of this article to show that such a concept is an oversimplification at variance with the facts. Similarly, it is usually assumed that following exercise an obese animal or person will increase food intake in direct proportion, whatever the intake prior to exercise or the energy expended in exercise. It has been shown (I) that in the hereditary obese hyperglycemic syndrome (2, 3), a decrease in voluntary activity (to less than 2 % of the normal in adult animals) is an essential aspect of the etiology of the obesity; this lack of activity was shown to precede the development of the obesity and is not simply a result of the overweight (I). When obese mice also carry the waltzing gene and are in nearly constant rotary movement in their cages, their weight rarely exceeds 40 gm instead of twice that value. In another report (4) it has been demonstrated that mice made obese by goldthioglucose injection (2) will lose weight if given the opportunity to practice unrestricted exercise. It is the purpose of the second part of this paper to show that the development of hereditary obesity in mice can be considerably slowed down by forcing these animals to exercise.

Jean Mayer

Papers

Regulation of energy intake and the body weight: the glucostatic theory and the lipostatic hypothesis.

From the Chicago MeetingsSarcopenia

Hypoferraemia in obese adolescents.

Exercise, Food Intake and Body Weight in Normal Rats and Genetically Obese Adult Mice

Relation between Caloric Intake, Body Weight, and Physical Work STUDIES IN AN INDUSTRIAL MALE POPULATION IN WEST BENGAL