The optimal management of overweight and obesity requires a mixture of diet, exercise, and behavioral modification. additionally, some patients eventually require pharmacologic therapy or bariatric surgery. the danger of overweight to the topic should be evaluated before beginning any treatment program. Selection of treatment can then be made employing a risk-benefit assessment. the selection of therapy depends on several factors including the degree of overweight or obesity and patient preference.
This topic will review the dietary therapy of obesity. Other aspects of treatment are discussed separately.
GOALS OF WEIGHT LOSS
— it’s important to line goals when discussing a dietary weight loss program with a personal patient. An initial weight loss goal of 5 to 7 percent of weight is realistic for many individuals.
• The first goal for any overweight individual is to forestall further weight gain and keep weight stable (within 5 pounds of its current level).
• The goal of the clinician is to spot and review with the patient a sensible weight loss goal. Most patients have a weight loss goal of 30 percent or more below current weight, which is unrealistic
• A successful program will result in a weight loss of quite 5 percent of initial weight A weight loss of quite 5 percent can reduce risk factors for upset, like dyslipidemia, hypertension, and DM In the Diabetes Prevention Program, a multi-center trial in patients with impaired glucose tolerance, weight loss of seven percent reduced the speed of progression from impaired glucose tolerance to diabetes by 58 percent .
• Loss of 5 percent of initial weight and maintenance of this loss may be a good medical result, whether or not the topic doesn’t reach his or her “dream” weight.
• Although a very difficult goal to realize, a body mass index (BMI) between 20 and 25 kg/m2 puts the topic within the lowest risk category
Rate of weight loss
— the speed of weight loss is directly associated with the difference between the subject’s energy intake and energy requirements. Reducing caloric intake below expenditure ends up in a predictable initial rate of weight loss that’s associated with the energy deficit However, prediction of weight loss for a private subject is difficult thanks to marked intersubject variability in initial body composition, adherence, and energy expenditure Food records are often inaccurate. Most normal-weight people under-report what they eat by 10 to 30 percent, while overweight people under-report by 30 percent or more additionally, energy requirements are influenced by fidgeting, gender, age, and genetic factors ]. As examples:
• Men lose more weight than women of comparable height and weight after they adjust to eating any given diet because men have more lean body mass, less percent body fat, and so higher energy expenditure.
• Older subjects of either sex have a lower energy expenditure and thus slenderize more slowly than younger subjects; rate declines by approximately 2 percent per decade (about 100 kcal/decade)
• The importance of genetic factors is illustrated by a study of identical male twin pairs who were overfed to induce weight gain Twelve twin pairs were overfed by 1000 kcal/day for 84 of 100 days. The degree of weight gain at a continuing dietary caloric increment varied widely among the dual pairs (from 4.3 to 13.3 kg), in fact, there was 3 times the variance for both weight and fat mass among the dual pairs compared therewith within the dual pairs.
Approximately 22 kcal/kg is required to take care of a kilogram of weight in an exceedingly normal adult. Thus, the expected or calculated energy expenditure for a lady weighing 100 kg is approximately 2200 kcal/day. The variability of ±20 percent could give energy needs as high as 2620 kcal/day or as low as 1860 kcal/day. a median deficit of 500 kcal/day should end in an initial weight loss of roughly 0.5 kg/week (1 lb/week). However, after three to 6 months of weight loss, energy expenditure adaptations occur, which slow the bodyweight response to a given change in energy intake, thereby diminishing ongoing weight loss
There are several methods of formally estimating energy expenditure; we recommend using the WHO criteria This method allows a right away estimate of resting rate (RMR) and calculation of daily energy requirement. The low activity level (1.3 x RMR) includes subjects who lead a sedentary life. The high activity level (1.7 x RMR) applies to those in jobs requiring toil or patients with regular daily workout programs
Maintenance of weight loss
— it’s important for the overweight subject to know that achieving and maintaining weight loss is created difficult by the reduction in energy expenditure that’s induced by weight loss Weight loss maintenance is additionally difficult due to changes within the peripheral hormone signals that regulate appetite. Gastrointestinal peptides, like ghrelin, which stimulates appetite, and gastric inhibitory polypeptide, which can promote energy storage, increase after diet-induced weight loss. Other circulating mediators that inhibit intake (eg, leptin, peptide YY, cholecystokinin, pancreatic polypeptide) decrease. These hormonal adaptations favoring weight gain persist for a minimum of one year after diet-induced weight TYPES OF DIETS — the final consensus is that excess intake of calories from any source, related to a sedentary lifestyle, causes weight gain and obesity. The goal of dietary therapy, therefore, is to decrease energy intake from food. Conventional diets are defined as those below energy requirements but above 800 kcal/day These diets comprise four groups: • Balanced low-calorie diets/portion-controlled diets
• Low-fat diets
• Low-carbohydrate diets
• Mediterranean diet
• Fad diets (diets involving unusual combinations of foods or eating sequences)
Commercial weight loss programs and internet-based programs are discussed elsewhere .) Balanced low-calorie diets — Planning a diet requires the choice of a caloric intake so selection of foods to fulfill this intake. it’s desirable to eat foods with adequate nutrients additionally to protein, carbohydrate, and essential fatty acids. Thus, weight-reducing diets should eliminate alcohol, sugar-containing beverages, and most highly concentrated sweets because they rarely contain adequate amounts of other nutrients besides energy. Breakdown of some protein is to be expected during weight loss. When weight increases as a results of overeating, approximately 75 percent of the additional energy is stored as fat and therefore the remaining 25 percent as lean tissue. If the lean tissue contains 20 percent protein, then 5 percent of the additional weight gain would be protein. Thus, it should be anticipated that in weight loss, a minimum of 5 percent of weight loss are protein. A desirable feature of any calorie-restricted diet, however, is that it leads to very cheap possible loss of protein, recognizing that this can not be but 5 percent of the load that’s lost. Portion-controlled diets — One simple approach to providing a calorie-controlled diet is to use individually packaged foods, like formula diet drinks using powdered or liquid formula diets, nutrition bars, foodstuff, and pre-packaged meals which will be stored at temperature because the main source of nutrients. Frozen low-calorie meals containing 250 to 350 kcal/package are often a convenient and nutritious thanks to try this. we’ve often recommended the utilization of formula diets or breakfast bars for breakfast, formula diets or a frozen lunch entree for lunch, and a frozen calorie-controlled entree with additional vegetables for dinner. during this way, it’s possible to get a calorie-controlled 1000 to 1500 kcal per day diet. In one four-year study this approach resulted in early initial weight loss, which then was maintained I don’t recommend the utilization of formula diets alone because they are doing not provide adequate nutritional variety. Low-fat diets — Low-fat diets are another standard strategy to assist patients reduce, and the majority dietary guidelines recommend a discount within the daily intake of fat to 30 percent of energy intake or less in an exceedingly meta-analysis of trials comparing low-fat diets (typically 20 to 25 percent of energy from fats) with a bearing group consuming a usual diet or a medium fat diet (usually 35 to 40 percent of energy), there was greater weight loss (approximately 3 kg) with low-fat compared with moderate fat diets additionally, one report noted that individuals who successfully keep their weight reduced adopt three strategies, one in all which is eating a lower fat diet A low-fat dietary pattern with healthy carbohydrates isn’t related to weight gain. This was illustrated by the Women’s Health Initiative Dietary Modification Trial of 48,835 postmenopausal women over age 50 years who were randomly assigned to a dietary intervention that included group and individual sessions to push a decrease in fat intake and increases in fruit, vegetable, and grain consumption (healthy carbohydrates), but failed to include weight loss or caloric restriction goals, or a sway group which received only dietary educational materials After a mean of seven.5 years of follow-up, the subsequent results were seen:
• Women within the intervention group lost weight within the first year (mean of two.2 kg) and maintained lower weight than the control women at 7.5 years (difference of 1.9 kg at one year, and 0.4 kg at 7.5 years).
• No tendency toward weight gain was seen within the intervention group overall, or when stratified by age, ethnicity, or body mass index.
• Weight loss was associated with the amount of fat intake and was greatest in women who decreased their percentage of energy from fat the foremost. A similar, but lesser trend was seen with increased vegetable and fruit intake. A diet may be implemented in two ways. First, the dietitian can provide the topic with specific menu plans that emphasize the employment of reduced fat foods. in concert guideline, if a food “melts” in your mouth, it probably has fat in it. Second, subjects will be instructed in counting fat grams as another to counting calories. Fat has 9.4 kcal/g. it’s thus very easy to calculate the amount of grams of fat an issue can eat for any given level of energy intake. Many experts recommend keeping calories from fat to below 30 percent of total calories. In practical terms, this suggests eating about 33 g of fat for every 1000 calories within the diet. For simplicity, i take advantage of 30 g of fat or less for every 1000 kcal. For a 1500-calorie diet, this is able to mean about 45 g or less of fat, which might be counted using the nutrition information labels on food package
— Proponents of low-carbohydrate diets have argued that the increasing obesity epidemic is also partially thanks to low-fat, high-carbohydrate diets. But this could be dependent upon the kind of carbohydrates that are eaten, like energy dense snacks and sugar or high fructose containing beverages. The carbohydrate content of the diet is a very important determinant of short-term (less than two weeks) weight loss. Low (60 to 130 grams of carbohydrates) and really low-carbohydrate diets (0 to <60 grams) are popular for several years Restriction of carbohydrates ends up in glycogen mobilization and, if carbohydrate intake is a smaller amount than 50 g/day, ketosis will develop. Rapid weight loss occurs, primarily because of glycogen breakdown and fluid loss instead of fat loss. Low and really low-carbohydrate diets are simpler for short-term weight loss than low-fat diets, although probably not for long-term weight loss. A meta-analysis of 5 trials found that the difference in weight loss at six months, favoring the low carbohydrate over low fat diet, wasn’t sustained at 12 months Low-carbohydrate diets may have another beneficial effects with reference to risk of developing type 2 DM, coronary heart condition, and a few cancers, particularly if attention is paid to the kind additionally because the quantity of carbohydrate. A low-carbohydrate diet is implemented in two ways, either by reducing the whole amount of carbohydrate or by consuming foods with a lower glycemic index or glycemic load Glycemic index and cargo are reviewed separately. .) If a low-carbohydrate diet is chosen, healthy choices for fat (mono- and polyunsaturated fats) and protein (fish, nuts, legumes, and poultry) should be encouraged due to the association between saturated fat intake and risk of coronary heart condition. During 26 years of follow-up of ladies within the Nurses’ Health Study and 20 years of follow-up of men within the Health Professionals’ Follow-up Study, low carbohydrate diets within the highest versus lowest decile for vegetable proteins and fat were related to lower all-cause mortality (HR 0.80, 95% CI 0.75-0.85) and cardiovascular mortality (HR 0.77, 95% CI 0.68-0.87 ]. In contrast, low carbohydrate diets within the highest versus lowest decile for animal protein and fat were related to higher all-cause (HR 1.23, 95% CI 1.11-1.37) and cardiovascular (HR 1.14, 95% CI 1.01-1.29) mortality High protein diets — Some popular books recommend high protein diets In one trial, low-fat diets with 12 percent and 25 percent protein content were compared. Weight loss over six months was greater with the upper protein diet (9 versus 5 kg), but the difference was not significant at 12 and 24 months Higher protein diets may improve weight maintenance, as illustrated by the results of a study of 60 subjects randomly assigned to an occasional fat, high protein versus low-fat, high-carbohydrate diet after completing a four week very low calorie diet Among the topics who completed the three-month study (n = 48), the high protein diet group had significantly better weight maintenance (between group difference of two.3 kg). High dietary protein intake, thanks to its acid-producing load, increases urinary calcium excretion (with potential risk for bone loss and calcium stone formation) Urinary calcium excretion does appear to extend when dietary intake of protein increases ], and this might pose a long-term risk for nephrolithiasis. However, two small randomized trials that checked out bone metabolism found evidence that increased dietary protein may decrease bone resorption ]. one in all the trials found that increased intestinal absorption of calcium was primarily liable for the increased urinary excretion of calcium which the excreted calcium wasn’t coming from bone Mediterranean diet — The term Mediterranean diet refers to a dietary pattern that’s common in olive-growing areas of the Mediterranean area. Although there’s some variation in Mediterranean diets, there are some common components that include a high level of monounsaturated fat relative to saturated; moderate consumption of alcohol, mainly as wine; a high consumption of vegetables, fruits, legumes, and grains; a moderate consumption of milk and dairy products, mostly within the kind of cheese; and a comparatively low intake of meat and meat products. A meta-analysis of 12 studies involving eight cohorts found that a Mediterranean diet was related to improved health status and reductions in overall mortality, cardiovascular mortality, cancer mortality, and incidence of brain disease and Alzheimers Very low-calorie diets — Diets with energy levels between 200 and 800 kcal/day are called “very low-calorie diets,” while those below 200 kcal/day are often termed starvation diets. the idea for these diets was the notion that the lower the calorie intake the more rapid the load loss, because the energy withdrawn from body fat stores may be a function of the energy deficit. Starvation is that the ultimate very obesity diet and ends up in the foremost rapid weight loss. Although once popular, starvation diets are now rarely used for treatment of obesity. Very low-calorie diets haven’t been shown to be superior to standard diets for long-term weight loss. in a very meta-analysis of six trials comparing very low-calorie diets with conventional low-calorie diets, short-term weight loss was greater with very low-calorie diets (16.1 versus 9.7 versus percent of initial weight), but there was no difference in long-term weight loss (6.3 versus 5.0 percent like all diets, very low-calorie diets initially lead to substantial protein loss that diminishes with time. Other expected effects include reduction in pressure and improvement in hyperglycemia in diabetic patients.
• Subjects adhering to very low-calorie diets usually have a fall in force per unit area, especially during the primary week. Antihypertensive drugs, especially calcium channel blockers and diuretics, should usually be discontinued when a awfully low calorie diet is begun unless moderate to severe hypertension is present.
• Most diabetic patients eating very low-calorie diets have marked improvement in hyperglycemia. blood sugar concentrations fall within the primary one to 2 weeks, and remain lower as long because the diet is sustained. Those patients taking but 50 units of insulin or an oral hypoglycemic drug will usually be able to discontinue therapy ]. The side effects of very low-calorie diets include hair loss, thinning of the skin, and coldness. These diets are contraindicated for lactating and pregnant women, and in children who require protein for linear growth. like all diets, there’s increased cholesterol mobilization from peripheral fat stores, thus increasing the chance of gallstones. Very low-calorie diets should be reserved for subjects who require rapid weight loss for a particular purpose, like surgery. the load regain when the diet is stopped is usually rapid, and it’s better to require a more sustainable approach than to use a way that can’t be sustained.