Obesity Treatment Options PDF

Obesity III Appetite: The psychology of eating and drinking 1 1 Treatment of obesity • The best thing we can do is to ensure that people do not become obese in the first place - prevention is best • That said, in this lecture (and the next) we will examine the treatment options that are currently...

Obesity III Appetite: The psychology of eating and drinking 1 1 Treatment of obesity • The best thing we can do is to ensure that people do not become obese in the first place - prevention is best • That said, in this lecture (and the next) we will examine the treatment options that are currently available for overweight/obesity • Although this lecture (and the next) examines these approaches in isolation, they are typically used in a combined manner • We will also look briefly at prevention today 2 2 Treatment options • We will look at the following strategies: – Diet (today) » 1200 different diet books on the market » Over 70% of adults claim to have tried one or more diet – Exercise (guidelines and effectiveness) – Behaviour therapy (aiding change and preventing relapse) – Drugs (limited choice at present) – Surgery (most effective option) • The type of strategy employed depends upon three things; age, health and BMI 3 3 Recommendations • The National Heart, Lung and Blood Institute in the US produced an authoritative set of evidence based guidelines to assist in picking the best treatment options BMI 25-26.9 27-29.9 30-34.9 35-35.9 >40 Category Overweight Overweight Moderately obese Severely obese Very severely obese Diet, exercise & behaviour therapy Y (with Y (with Y Y Y comorbidities) Low fat diet comorbidities) Low fat diet Low fat diet Very low fat diet Very low fat diet Drugs N Y (with Y Y Y comorbidities) Orlistat & CNS Orlistat & CNS Orlistat & CNS N Y (with Y comorbidities) Banding, Sleeve Banding, Sleeve Orlistat & CNS Surgery 4 N N 4 Diet - Introduction • As we know the cause of obesity is energy intake (eating) exceeding energy expenditure (exercise etc) • The most obvious strategy is to reduce energy intake - that is to diet • There are many forms of diet – These range from the evidenced based to the farcical – Most commercial diets have no evidence base • Some are so far fetched that it is very unlikely anyone would ever bother to test them (e.g., ‘detox diets’ are the most depressing of this class [e.g., lemon detox diet or skinny me tea…] or ones relying upon some magic ingredient [e.g., chia, apple cider vinegar, green tea extract…] or device [e.g., magnetic rings]) – All diets that work, work in the same basic way – they reduce the amount of energy you are consuming – This then leads to a state of negative energy balance – The body then starts to burn its fat supplies and so weight loss begins 5 5 Diet – basics I • There are really only a limited set of parameters that any diet (that might reasonably work) can play with – The principal variable is macronutrient content • That is the proportion of fat, protein and carbohydrate in the diet • One could also add in here whether you are preparing the food or whether it is being prepared for you – – – – – – Glycemic index Solid versus liquid Portion size modification Eating rate modification (chewing rate) Energy density (low energy density diet – high fibre water content) Fasting 6 6 Diet – basics II • Irrespective of what is being modified, to be effective a diet needs to get you eating around 14-1500 Kcal/day • Even if this diet consisted of big macs and fries, if it is 141500 Kcal/day you will lose weight • The gold standard diets, successful commercial diets and those studied scientifically include • Low Fat (the nutritional gold-standard; Jenny Craig, Weight Watchers; Very-low fat diets – Pritkin, Ornish diets) • Emphasising high Protein (Zone, Paleo diets) • Emphasising low Carbs (Atkins, Sugar Busters, South Beach diets) • Low Glycemic index (GI) • Mediterranean diet (good fat, limited meat, high fruit, veg & fish) • We will review their efficacy and health impacts 7 7 Fat reduction diets • Fat is the most energy dense macronutrient • Therefore, reducing each gram of fat in a diet has more effect (in terms of reduced energy intake) than reducing equivalent amounts of protein or carbohydrate – Traditionally, it was also thought that removing saturated fats would yield additional health benefits • For these reasons low fat diets have been the traditional approach adopted by nutritionists and are the mainstay of most medical interventions – They are also important commercially • Not surprisingly then, they are the best studied 8 8 How do you evaluate a diet? • To evaluate a diet program we need three key things – A good sample size (500+ because of attrition to follow up & effect size) – A treatment and a control group (an appropriate control is tricky to design – similar level of contact, information, motivation etc) – Random allocation to these groups • Success is generally defined as a loss of 5% of initial body weight at one-year (contrast this with peoples expectations which is 1/3 of initial body weight or about 30% weight loss!) • Three large scale trials have evaluated low fat diets and there have been multiple small scale trials of several commercial programs that can be pooled for meta-analysis • A low fat diet is defined here as obtaining around 20% of your energy from fat • With a target of 1500Kcal/day – that is 30g of fat/day – Contrast this with the average US diet of 2200Kcal/day – Of which 35% of energy is from fat (i.e. 85g of fat/day) – That is a big change! 9 9 Do they work? • In these three studies participants were evaluated at 6 months (2 studies) and 12 months (1 study) - all worked Study PREMIER DPP FDP (all used people with BMI > 30) (n=810) (n=3234) Diab. Prevention (n=522) Finnish Diab. Prev. Control (kg lost) 1.1 0.1 0.8 5.4 (@ 6M) 3.9 (@ 6M) 4.2 (@ 12M) (+ improved glucose tolerance & maintained to 2 years follow-up) (+ improved glucose tolerance & maintained to 2 years follow-up) (Just diet advice) Treatment (kg lost) (diet + monthly visits; around 20 wks duration) • These parallel findings from studies of Weightwatchers and Jenny Craig in terms of effectiveness 10 10 Very low fat diets • People who are morbidly obese may require more drastic dietary interventions • May be used as a test of motivation for surgery and to get weight down to a level where the person will survive anaesthesia • These are commercially available too (e.g., Pritkin, Ornish, Medifast, OPTIFAST) • One which has been commonly used is to reduce energy intake from fat to less than 5% with then an overall energy intake of around 1000-1200Kcal/day • These diets result in larger initial weight loss (10kg at 6 months), but weight regain over 1-5 years may make them no more efficient (long term) than low-fat diets • Note fewer & smaller studies (n < 100; so less reliable) • May also produce additional gains for coronary artery stenosis 11 11 Fat reduction - conclusion • They work - but they are hard work • Fat makes food palatable, its loss impacts on the pleasure obtained from eating • However, low fat dieters often claim they have too much food! • An additional benefit is that LF diets may alter preference for fat • A further consideration is the type of fat consumed • Although low fat diets reduce energy intake, diets that concentrate on eating good fats (mono and poly-unsaturated fats) can also produce additional health gains, such as reduced cholesterol, coronary artery stenosis and glucose tolerance • One example is the ‘Mediterranean’ diet which combines ‘good’ fats, with an overall healthy diet 12 12 Mediterranean (Med) diet I • The potential of the med diet was first recognised by Ancel Keys in the 1940’s • Although the diet is pretty similar in fat content to a North American diet it differs in several important ways – ‘Good’ fats such as olive and fish oils predominate – High in fibre – Main source of energy is low GI carbohydrates – Limited red meat – Lots of fruit and vegetables 13 13 Mediterranean (Med) diet II • Unfortunately, there have been very few clinical trials of the Med diet, so it is hard to discern its effects on body weight (i.e., as a diet tool) – Epidemiological studies suggest that this type of diet is associated with lower risk of heart disease, longevity (Ancel Keys lived to 100) and better cognition into old age • Some other regional diets may offer similar benefits, such as the traditional Japanese diet high in complex carbohydrates and fish – There must be something beneficial to it, as there are over 60,000 centenarians in Japan – 3X more % wise than in the USA 14 14 High protein diets • High protein diets (e.g., Zone or Paleo diet) essentially up protein levels, at the expense of fat and especially carbs – The Paleo diet is based on the dubious premise that we should eat what our ancestors ate (i.e., the diet we are ‘optimally’ adapted for) – Unfortunately, there is a lot of uncertainty over what they ate, and even when they ate the same food is probably different now (e.g., fat profile and content of wild vs farmed meat) • Far fewer studies have been conducted on this type of diet, none of which meet our ‘strict’ criteria • The best one available allocated 50 overweight and obese individuals to two diets, both equivalent and low in calories • One diet was low in protein (Energy: 12% protein*, 30% fat, 58% carbs) [*note dietary guidelines suggest 18% for protein] • The other was high in protein (Energy: 25% protein*, 30% fat, 45% carbs) • All the food was provided to ensure compliance for the first 6 months (6-12 months self-preparation) 15 15 Do they work? • The high protein group lost more at 6 months (9.4Kg) than the low protein group (5.9Kg) – At two years, there was no significant difference in weight loss – However, many subjects were lost to follow-up (power) – Trend for greater weight loss remained • The high protein group demonstrated additional gains, notably a greater reduction in abdominal fat – This gain was maintained to follow-up • These results are comparable in magnitude to low fat diets, a key question is whether it is easier for someone to maintain them • Extra weight loss might result from greater satiation produced by the high protein diet 16 16 Low carbohydrate diets • In this class of diet (e.g., Atkins, Sugar Busters, South Beach) the primary aim is to especially reduce carbs and up protein (and fat) intake • The Atkins diet is the most well known example • Atkins claims 20M people have used his diet • According to Atkins no dietary restriction is required as the nature of the food (protein) result in excess weight loss • This is untrue - it works like all other diets - calorie restriction • Several studies have now examined low carb diets, most by comparing them to low fat diets – The conclusions are based on meta-analysis of lots of small scale studies, so the evidence base is weak • They are as effective as low fat diets, but they may have a slight edge 17 17 Low carb diets • The evidence is not complete as there have not been sufficient large scale trials to decide whether low carb diets are really superior to low fat diets • This is a hotly debated issue – Some claim that the extra weight loss is produced by the water needed to metabolise the extra dietary protein – Stop the diet and the water comes back and weight loss is then the same as low-fat diets • In addition there are some safety concerns • These are not well understood and may include – – – – Renal failure and osteoporosis Unsuitable for certain patient groups (high BP & Kidney disease) Long term costs vs benefits not evaluated Could increase the risk of heart disease 18 18 Low carb diets - conclusion • The benefits • A key issue here may be that compliance is easier • Protein is more satiating • Low carb diets tend to restrict foods that contribute less to meal enjoyment Atkins Low-fat diet Breakfast - 2 scrambled eggs, bacon & coffee Lunch - Bacon, cheeseburger, salad Dinner - Soup, shrimp salad, steak, salad, jelly & cream Breakfast - Cornflakes, low-fat milk, slice of toast, orange Lunch - Beef sandwich, 2 raw carrots, cup of milk, 10 grapes Dinner - Almonds, fig bar, beef stock, 2 crackers, salmon, zucchini and 1/2 baked potato 19 19 Low GI diets • Glycemic index refers to the rate at which blood sugar rises following carbohydrate intake • A food with a glycemic index of 100 is one which raises BSL at the same rate as glucose, white bread or mashed potato • Carbohydrates that have lower GI’s are considered healthier as they result in longer periods of satiety following a meal (i.e. sustained energy release) and lower peak BSL • Carbohydrates are typically grouped into three GI categories – High (70+; refined sugar & flour products, potato, cornflakes) – Intermediate (55-70; raisins, long-grain rice) – Low (54-; apples, legumes) • Only limited diet effectiveness studies (i.e., all small sample sizes) – No advantage in terms of weight loss over equicaloric high GI diets (i.e., both work equally well) with effects in the same range as low fat diets – Low GI diets may especially help obesity related metabolic disorders (type II diabetes) and cardiovascular complications (i.e. an advantage beyond that offered by weight loss alone) » Better control of BSL, improved insulin resistance, reduce ‘bad’ cholesterol 20 20 Diets - General considerations • We will now turn to look at some broader issues which relate to all types of dieting • • • • • What best predicts success at weight loss Maintenance of weight loss What predicts long term success Dieting in children How to encourage healthy eating (prevention) 21 21 What predicts weight loss success? • The single best predictor of how well a diet will work is the length of the formal treatment phase, which is why most peoples attempts at dieting do not work well (a typical self-imposed diet is 4-6 wks) Year 1970’s (15) Early 80’s (15) Late 80’s (18) Early 90’s (8) Mean treatment length (weeks) 8.4 13.2 17.2 21.5 Mean % weight loss 5 8 10 9 (number of studies) 22 22 Maintenance • Almost irrespective of the diet employed the pattern illustrated below appears to hold true • This does not mean that dieting is useless, rather that the absolute gains are rather modest - around 3-4% of initial body weight on average at 4 years 23 23 What helps maintenance • Treatment length (yes) – However, compliance becomes a problem with long programs – Telephone/email contact not any good, it has to be face-to-face • Multicomponent treatment (yes) • Motivation enhancement (no) – 25$/wk dependent on progress VS no payment – Deposit studies • Relapse prevention (possibly) – Not very successful – However, work for addictions and so may need adapting better to dieting 24 24 What makes for a successful dieter? • Wing & Hill have compiled a database of people (The National Weight Control Registry), who of their own free will, have lost over 20Kg and maintained this loss for at least 5 years • They currently have over 2500 people on this register - so it is possible to lose a lot of weight and keep it off • What characterises this group? – They exercise an hour+ each day at moderate intensity – They consume only 1400Kcal per day – They are vigilant about their weight (44% have a daily weigh-in) • These individuals are, however, the lucky few (guesstimates put them at about 2% of dieters) and they clearly have to work hard to maintain their weight 25 25 Dieting in children • With the increasing number of overweight and obese children attention is being paid to dieting in children • Here the story is rather different • Dieting is more successful in this group with gains of 10-15% weight loss even at 10 year follow-up • One probable reason is that such diets can be policed by parents 26 26 Promoting healthy diets • The emphasis of all treatment regimes for overweight/obesity is one focused on the individual (i.e., overweight is your problem) • As we have seen with dieting, large changes in weight (and maintaining them) are difficult for most people • A more realistic approach is to take a public health perspective, with the view that small changes amongst many people will have more impact than big changes amongst a few • So what sort of things can be done? 27 27 Health promotion and diet I • Thinking differently • It is an environmental problem first – In the US there have been 36 sets of guidelines from federal and private bodies about maintaining a healthy weight since 1952. YET ONLY 1 HAS FOCUSSED ON ENVIRONMENTAL CHANGES - this emphasis needs to change • Physical activity • Increase it – 70% of Australians take too little or no exercise – How to remedy this? » Rethinking the built environment (are things in walking distance?) » Putting fitness back as a central component of schooling » Equal access to exercise space and facilities 28 28 Health promotion and diet II • Limit the commercialisation of childhood – An average child views 1000 junk food adverts on TV/year – We would not condone selling tobacco and alcohol to children, why should we accept the sale of junk food? • Food and soft drinks in schools – Provide health foods reduce access to soft-drinks (this is happening) • Reduce portion size – A “super” serve of fries provides 30% of ones daily energy needs, yet there are no similar incentives for consuming healthy food • Change the price structure of food – Junk food is cheap, readily available and stores well - unlike fruit and veg – “Fat tax” or “Sugar tax” may be one way to remedy this disparity • The food industry – Engagement and pressure - draw lessons from the history of the “tobacco wars” 29 29 Conclusion - diets • In this lecture we have looked at the principal approach adopted to control weight gain - diet • Diets do work, but they are really not that effective longterm • It is very hard work to stay within a strict weight band once weight has been lost • Overall, it is probably far better to try and curb weight gain • In the next lecture we will examine other approaches to treatment, as well as some psychosocial issues connected with body perception and weight 30 30