The history of weight gain

—The history of weight gain is most helpful in considering underlying causes

—A patient who has

—recently begun to gain substantial weight for the first time or

—at a faster rate than previously, and

—is not taking relevant drugs

—is more likely to have an underlying disorder such as hypothyroidism or Cushing's syndrome

—A more detailed history and examination should be performed with these conditions in mind

—Monogenic and 'syndromic' causes of obesity are usually only relevant in children presenting with severe obesity

Investigations

—Thyroid function tests – should be performed on one occasion

—Overnight dexamethasone suppression test or 24-hour urine free cortisol if Cushing's syndrome is suspected.

—blood glucose and a serum lipid profile, ideally in a fasting morning sample- for the presence of associated type 2 diabetes and dyslipidaemia

—Serum transaminases-  Elevated in patients with non-alcoholic fatty liver disease

Management

—The health risks of obesity are largely reversible

—All interventions which have been proven to reduce weight in well-conducted studies in obese patients have also been shown to ameliorate cardiovascular risk factors

—Lifestyle advice which lowers body weight and increases physical exercise reduces the incidence of type 2 diabetes

—Given the high prevalence of obesity and the large magnitude of its risks, population strategies to prevent and reverse obesity are high on the priority list for most health organisations

—Initiatives include

—promoting healthy eating in schools,

—enhancing walking and cycling options for commuters, and

—liaising with the food industry to reduce energy and fat content and label foods appropriately

—Most patients seeking assistance with obesity are motivated to lose weight but will have attempted weight loss previously without long-term success

—They may hold misconceptions that they have an underlying disease, inaccurate perceptions of their energy intake and expenditure, and an unrealistic view of the target weight which they would regard as a 'success’

—An empathetic explanation of energy balance, which recognises that some individuals are more susceptible to obesity than others and therefore require greater deficits in energy balance in order to lose and sustain body weight, is important

—Exclusion of underlying 'hormone imbalance' with simple tests is reassuring and shifts the focus on to consideration of energy balance

—Appropriate goals for weight loss should be agreed, recognising that the slope of the relationship between obesity and many of its complications becomes steeper with increasing BMI, so that a given amount of weight loss achieves greater risk reduction at higher levels of BMI

—A reasonable goal for most patients is to lose 10% of body weight

—The specific management plan will vary according to the severity of the obesity and the associated risk factors and complications

—Instead most guidelines focus resources on short-term interventions in those who have high health risks and comorbidities associated with their obesity, and who have demonstrated their capacity to alter their lifestyle to achieve weight loss

Lifestyle advice

—Behavioural modification to avoid some of the effects of the 'obesogenic' environment is the cornerstone of long-term control of weight

—A study of subjects followed up after successful weight loss in Colorado found that the principal predictors of sustained weight loss are the maintenance of high physical activity levels and the regular consumption of breakfast (suggesting a regular eating pattern)

—All patients should be advised to maximise their physical activity

—Where possible, this should be incorporated in the daily routine (e.g. walking rather than driving to work) since this is more likely to be sustained

—Alternative exercise, e.g. swimming, may be necessary if musculoskeletal complications prevent walking

—Changes in eating behaviour

—food selection,

—portion size control,

—avoidance of snacking,

—regular meals to encourage satiety, and

—substitution of sugar with artificial sweeteners

—Participation in a group discussion may be helpful.

Weight loss diets

—In overweight people, adherence to the lifestyle advice above may gradually induce weight loss

—In obese patients, more active intervention is usually required to lose weight before conversion to 'weight maintenance' advice above.

—The goal is to lose ∼0.5 kg/week

—Weight loss is highly variable, with patient compliance being the major determinant of success

—Compliance is better with moderate relative reductions of ∼600 kcal in daily calorie intake than with 'fixed' regimes of 1000 kcal intake per day, which may represent a reduction of > 1500 kcal/day in many patients

— There is some evidence that weight loss diets are most effective in their early weeks, and that compliance is improved by novelty of the diet; this provides some justification for switching to a different dietary regime when weight loss slows on the first diet

—Vitamin supplementation is wise in those diets in which macronutrient balance is markedly disturbed.

—In some patients more rapid weight loss is required, e.g. in preparation for surgery

—There is no role for starvation diets which carry a risk of sudden death from heart disease, exacerbated by profound loss in muscle mass and the development of arrhythmias secondary to elevated free fatty acids and deranged electrolytes

—Very low calorie diets (VLCDs) produce weight losses of 1.5-2.5 kg/week compared to 0.5 kg/week on conventional regimes, and hence require the supervision of an experienced physician and nutritionist

—Unfortunately, most patients regain weight after stopping such a diet, so VLCDs are mainly used for short-term rapid weight loss.

—The composition of the diet should ensure a minimum of 50 g of protein each day for men and 40 g of protein for women to minimise muscle degradation

—Energy content should be a minimum of 1.65 MJ (400 kcal) for women of height < 1.73 m, and 2.1 MJ (500 kcal) for all men and for women taller than 1.73 m.

—Side-effects tend to be a problem in the early stages and include orthostatic hypotension, headache, diarrhoea and nausea

Drugs

—Two drugs are currently available and newer agents are likely to be approved and marketed soon

—There is no role for diuretics, or for thyroxine therapy without biochemical evidence of hypothyroidism

—Currently recommended

—Orlistat -Pancreatic lipase inhibitor

—Sibutramine -Serotonergic in CNS

—In advanced development

—Rimonabant - Cannabinoid receptor antagonist

—Not recommended as primary treatment; weight loss a useful minor/temporary effect

—Fluoxetine

—Metformin

Orlistat

—Orlistat inhibits pancreatic and gastric lipases and thereby decreases the hydrolysis of ingested triglycerides, reducing dietary fat absorption by ∼30%

—The drug is not absorbed and adverse side-effects relate to the effect of the resultant fat malabsorption on the gut, namely loose stools, oily spotting, faecal urgency, flatus and the potential for malabsorption of fat-soluble vitamins.

—Orlistat is taken with each of the three main meals of the day and the dose can be adjusted (60-120 mg) to minimise side-effects

—'In patients with a BMI > 30 kg/m2, 4 years of treatment with orlistat + lifestyle advice, in comparison with placebo + lifestyle advice, increased weight loss from 3.0 to 5.8 kg and reduced the incidence of type 2 diabetes from 9.0% to 6.2%. Orlistat also improved blood pressure and serum lipid profile

—Its efficacy may be explained because patients taking orlistat adhere better to low-fat diets in order to avoid unpleasant gastrointestinal side-effects.

Sibutramine

—Sibutramine reduces food intake through β1-adrenoceptor and 5-HT2A/2C (5-hydroxytryptamine, serotonin) receptor agonist activity in the central nervous system

—Weight loss achieved with this agent is 3-5 kg better than placebo with 6 months' therapy and is associated with an improvement in lipid profile

—Side-effects include dry mouth, constipation and insomnia

—Unfortunately, noradrenergic effects of the drug can increase heart rate and blood pressure;

—These effects are especially undesirable in many obese patients, so that this agent is usually a second choice after orlistat and cannot be used in those with hypertension or cardiovascular disease.

—There is insufficient evidence to recommend co-prescription of orlistat and sibutramine.

Rational Use

—Drug therapy is usually reserved for patients with high risk of complications from obesity , and its optimum timing and duration are controversial

—Patients who continue to take anti-obesity drugs tend to regain weight with time

—Anti-obesity drugs are used in the short term to maximize the weight loss achieved with low calorie diets (so that inevitable regain of weight starts from a lower baseline), but are not used in the long-term maintenance of weight

—It follows that they should only be introduced in patients who are demonstrating their adherence to a low calorie diet by current weight loss (e.g. recent weight loss of at least 2.5 kg) and should only be continued while patients continue to lose weight (e.g. at least 5% every 3 months)

Surgery

—'Bariatric' surgery to reduce the size of the stomach is by far the most effective long-term treatment for obesity

—Bariatric surgery should be contemplated in patients

—who have very high risks of complications of obesity ,

— in whom extensive dietary and drug therapy has been ineffective or inadequately effective, and

—who are motivated to undergo surgery.

—Only experienced specialist surgeons should undertake these procedures.

ECTOPIC PREGNANCY: http://ectopicpregnancyinwomen.blogspot.com/

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