Popular older diets.pdf

Assessment of Popular Diets – Older diets NUTR 344 – Winter 2024 Reading Material • Freedman MR, King J, Kennedy E. 2001. Popular diets: A scientific Review. Obesity Research. 9(S1):1S-40S • à Executive Summary: Mandatory • Ting R et al. Ketogenic diet for weight loss. Can Family Phys 64: 906, 201...

Assessment of Popular Diets – Older diets NUTR 344 – Winter 2024 Reading Material • Freedman MR, King J, Kennedy E. 2001. Popular diets: A scientific Review. Obesity Research. 9(S1):1S-40S • à Executive Summary: Mandatory • Ting R et al. Ketogenic diet for weight loss. Can Family Phys 64: 906, 2018 References: • Gardner CD et al., The DIETFITS randomized clinical trial, JAMA 319;7, 667-679, 2018. • Freedhoff Y and Hall KD. Weight loss diet studies: we need help not hype. Comment in Lancet 2016. Characteristics of weight loss diets 1. Nutritionally balanced (>1200 kcal) 2. Nutritionally unbalanced (800 - 1200 kcal) 1. low carbohydrate (high fat and/or protein) 2. low fat (high carbohydrate and/or protein) 3. Calorically dilute : high fibre, low fat 4. Fasting/semi-fasting: VLCD (<600 - 800 kcal) “fasting” (<500 kcal) 1. Nutritionally Balanced Type of diet Unrestricted kcal Description Characteristics Liquid homogenate Monotonous Varied items Mixed low-calorie diet (1200 kcal) Carefully controlled caloric intake, palatable Formula Liquid homogenate Carefully controlled caloric intake, monotonous Restricted kcals 2. Nutritionally Unbalanced Type of diet Description Characteristics Altered proportion of macronutrients Low fat, high carb or protein Reduced efficiency of calorie utilization; reduced fat deposition; difficult to compensate for excluded foods Altered proportion of macronutrients Low carb, high fat or protein Ketosis; decreased appetite; small excretory loss of calories; difficult to compensate for excluded foods Specific food item focus Grapefruit, kelp, cabbage Very reduced caloric intake, soup monotonous 3. Calorically Dilute Type of diet Calorically dilute Description High fiber, low fat Characteristics Slowed ingestion rate (more chewing required), impaired digestion/absorption of nutrients, satiety-inducing 4. Fasting Type of diet Description Characteristics Very low-calorie diets Protein-sparing modified fast (PSMF) Specific food item focus Protein or prot/carb mixtures, 600-800 kcal/day Reduced body fat, spare body protein?, ketosis Reduced body fat, highly ketogenic Classification of Plans – Older diets High fat/Low carb Moderate fat (balanced) Low/Very low fat Food combining Other Carb Addict’s Weight Watchers Ornish-Eat more Weigh Less Montignac The Zone (low carb) Volumetrics Pritikin Principle Protein power Atkins Fit for Life Red Flags for Program and Product Claims • Lose > 1 kg/wk without cutting calories or increasing physical activity • Lose a lot of weight while eating a lot of high-calorie foods • Weight loss will be permanent – it will stay off even after stopping • OTC product blocks absorption of fat or calories • Lose > 1 - 2 kg/wk for over 4 wks • Product is worn or rubbed into the skin • Suitable for anyone to use Issues to consider when assessing contemporary weight loss plans or diets • Are they nutritionally adequate? Is any food group excluded? • Based on food groups and DRIs • Do they produce weight loss for all individuals? • Using estimated energy expenditure and assuming that 0.5 kg loss = 3500 kcal deficit (i.e. – 500 kcal/d) • Do they comply with healthy guidelines (CVD, diabetes, hypertension)? Significance of Food Group Evaluation Food group Milk products Nutrients Calcium, Vitamin D, riboflavin, protein Consequences if you remove it Bone pain, muscle weakness Meat and Alternatives Protein, iron, zinc, fat Hair loss, dry hair and skin, fatigue, anemia Fruits and vegetables Antioxidants, fiber, vitamins, minerals Constipation, bleeding gums Grain products Constipation, lack of energy Carbohydrates, B vitamins, fiber High Fat/ Low Carbohydrate diets • Atkins - Protein Power - Keto diet • Philosophy/Rationale: Chronically high insulin levels lead to insulin resistance Create an environment in which I/G is decreased Glucagon shifts body into “fat burning mode” Blood sugar determines which of these hormones prevail • Blood sugar is regulated through food choices • • • • don’t need to know this, just needs to know that it’s been forever Popular Diets Involving Low Carbohydrate (<60 g/d) Intake Atkins diet • Original: 60-65% fat, <20g CHO don’t need to know exactly what are allowed and not, but just that high fat low carbs Atkins new diet - principles Atkins new diet - Menu example Assessment: Atkins diet • Potential harms: • High in saturated fats: CVD risks? • Low in fiber, B vitamins • Potential benefits: • • • • Low in added sugars May improve diet quality in some Reduced calories for most people Reduced serum triglycerides Ketogenic diet • 1920 - Therapeutic diet to treat epilepsy seizures in children refractory to medications • 90% fat à 60% fat from MCT medium chum TG • Classic ratio 4:1 (fat: CHO + pro) • Current revived popularity for weight loss • Rationale: • Low carb – low insulin – burning fat • Suppression of appetite à easier to sustain over time What is a ketogenic diet? • Very low carbohydrate, high fat, moderate protein diet • 6-12% CHO • 60-70% Fat • 20-30% Protein • Less than 35-50 g CHO per day to induce ketosis, often less • Diet should not include: • • • • grains fruits starchy vegetables (tubers, root vegetables) added sugars Average daily weight change during 10-day experimental and 5-day post-experimental diets kept losing a bit of weight increased in weight Average daily composition of weight change during 10-day experimental and 5-day postexperimental diets Longer term efficacy of ketogenic diet for weight loss – Summary of evidence • Systematic review (13 RCTs) keto vs. low-fat diet: 0.9 kg more weight loss with keto at 12 and 24 mo. Statistically significant but clinically meaningless. • Systematic review (11 RCTs) keto vs. low-fat diet: 2.2 kg more weight loss with keto at 6 and 24 mo. Inconsistent results, higher-quality studies showed no differences. • No systematic review examined mortality or CVD risk. • Recent (best ever) RCT (n=609) found 6.0 kg loss with keto vs. 5.3 kg with low-fat diet (not statistically different), see DIETFITS next slide. Ting R. et al. Can Fam Physician 64, 2018 DIETFITS Randomized Clinical Trial to see if ppl who had more insulin would lose less weight —> unpredictable can’t know in advance how someone will respond to a diet, especially ketogenic Data modeling from the DIRECT trial Side/Adverse Effects of Ketogenic Diets Short-term (days/weeks) • Common (≅ 30%) • Constipation, halitosis, muscle cramps, headache, diarrhea, weakness, rash • Irritability • Insomnia • Lower exercise tolerance your body needs to get use to use fat as fuel and not CHO • Hyperuricemia Side/Adverse Effects of Ketogenic Diets hard to maintain diets, so don’t have a lot of info on long-term outcome (studies go usually to max a year) Longer-term effects: • Elevated serum LDL-C * when isocaloric • Water soluble vitamin deficiency • Carnitine deficiency • Renal stones • Acidosis & excess ketosis during illness • Optic neuropathy (thiamine deficiency) In treatment of epilepsy in children: • Growth inhibition • Lower bone density and growth Low Fat/ High Carbohydrate diets • Ornish (Eat More Weigh Less) – Pritikin Principle • Philosophy/rationale: • Stems from “Lifestyle Heart Trial” • CHD can be reversed through lifestyle changes • Weight loss secondary effect • All calories are NOT created equal • Fat more readily converted to fat • Low fat / High fiber meals promote “fullness” • Eating less prolongs life • Promises to INCREASE metabolism Food Categories Ornishʼs Eat More Weigh Less Unlimited quantities In moderation Avoid completely Specific foods Beans, legumes, grains, fruits, vegetables Non-fat dairy, non-fat or very low-fat commercial products (<2 g fat/serving) All meats, oils, avocado, nuts, seeds, olives, egg yolks, simple sugars, alcohol, other dairy products Assessment – Ornish diet • Potential harms: • Low in liposoluble vitamins, essential fatty acids • May be high in sugar • Potential for gaining weight (average menu 1800 kcal) • Potential benefits: • May improve diet quality in some • Reduced calories in most • Improved lipid profile & CVD risk Moderate fat – Balanced diets Volumetrics • Based on principle of energy density, ED = kcal/g of food • Eat larger portions while consuming fewer calories Structure and Guidelines Volumetrics • Weight x factor (12-17) = Energy for wt maint. • Subtract 500 calories to lose 1 pound/week • Various levels of the plan: • 1400, 1600, 1800….2600 calories • No set menu • Dieter chooses between 12 breakfasts, 10 lunches, 25 suppers Montignac Philosophy Rationale Montignac • France and Quebec versions • Hyperinsulinemia is the cause of obesity • Glycemic Index (GI) is tool to controlling insulin levels and maintaining healthy pancreas • “Good Carbohydrates” • Low GI (less than 50)– limits fat storage • Whole grain flour, brown rice, legumes, most fruit, fiber containing vegetables • “Bad Carbohydrates” • High GI (more than 50)– increases insulin and favors storage • Table sugar, white flour, white rice, corn, potatoes, carrots Glycemic Index Structure and Guidelines Montignac Sample Meal Combinations (Phase I and II) Structure and Guidelines Montignac • Calculate BMI consider age, gender, food history, genetics to determine rate of weight loss • Phase I (weight loss) • Avoid: bad carbohydrates, caffeine, soft drinks, fruit juices, alcohol • Fruit to be eaten on an empty stomach • Protein-lipid (meat fish dairy or legumes and GI <35) OR carbohydrateprotein (GI < 50) • Phase II (maintenance) • “Controlled Freedom” – slightly higher GI but must compensate the next day. • Alcohol allowed (0.5 bottle of wine/ day at lunch) • Food combinations still important Conclusions • Bottom line: Those diets lead to kcal reduction • Weight loss is NOT guaranteed on all plans • will occur with energy restriction, but unpredictable in long-term • CVD risks unknown with high fat diets • Several diets are nutrient inadequate, especially extreme • Calcium, vitamin D, vitamin E, thiamin, zinc, iron • No educational component, poor long-term adherence, risk of weight regain Adverse effects of severe dieting • Gallstones formation • Osteoporosis • Weight cycling (yo-yo): • Favors weight regain • Impact on eating behaviors: 30-50% have compulsive behaviors • Devastating impact on self-esteem Contraindications to VLCD: Absolute Malignant arrhythmias Unstable angina Protein wasting diseases (e.g. lupus, Cushing’s syndrome) Major system failure (e.g. liver or renal failure) Drug therapy causing protein wasting (steroids, antineoplastic agents) • Body weight at BMI < 27 • Pregnancy or lactation • • • • • Adapted from: Atkinson,R., 1988. Medical Management of VLCD in NIDDM. On the Cutting Edge: Dieticians in Diabetic Care and Education Newsletter 9:3. Contraindications to VLCD: Relative • Congestive heart failure • Drug therapy with potassium wasting diuretics, adrenergic stimulating agents • History of failure of compliance with medical regimens • Body weight at BMI < 30 • Substance abuse Adapted from: Atkinson,R., 1988. Medical Management of VLCD in NIDDM. On the Cutting Edge: Dieticians in Diabetic Care and Education Newsletter 9:3. Contraindications to VLCD: Cautions • • • • Angina or history of heart disease Presence of systemic disease History of psychiatric or emotional disorder Chronic drug therapy (insulin, oral hypoglycemics, antiinflammatory agents, psychotropic agents, etc.) Adapted from: Atkinson,R., 1988. Medical Management of VLCD in NIDDM. On the Cutting Edge: Dieticians in Diabetic Care and Education Newsletter 9:3.