350 likes | 475 Views
The New Dietary Guidelines: Lessons Learned and Researchable Issues F. Xavier Pi-Sunyer, M.D. Columbia University. The most prevalent chronic disease we now face is obesity, and obesity leads to:. Diabetes Cardiovascular disease Cancer Arthritis Pulmonary disease.
E N D
The New Dietary Guidelines:Lessons Learned and Researchable IssuesF. Xavier Pi-Sunyer, M.D.Columbia University
The most prevalent chronic disease we now face is obesity, and obesity leads to: • Diabetes • Cardiovascular disease • Cancer • Arthritis • Pulmonary disease
What Causes a Population to Become Obese? Energy Expenditure Physical Activity Energy Intake Caloric Intake
American Paradox: 2004 • An escalating trend towards poor nourishment and health in a land of plenty • Because of sedentary lifestyles and poor food choices, many Americans exceed their caloric needs without meeting their nutrient requirements.
How to meet nutrient requirements and prevent weight gain? • “Consume a variety of foods within and among the basic food groups, while staying within energy needs.” • “Limit caloric intake, especially from added sugars, solid fats, and alcoholic beverages.”
Dietary Factors That Affect Energy Intake Energy density Nutrient composition Portion size Energy intake Variety Cost Availability 7
Nutrient Composition: what are the optimal proportions of dietary fat and carbohydrate to maintain BMI and to achieve long-term weight loss? • Components? • Higher fat ? • 20-35% • Higher carbohydrate? • 45-65% • Protein? • 10-35% • Long range studies needed
What Is the Relationship Between Portion Size and Energy Intake? • “The amount of food offered to a person influences how much he or she eats; and, in general, more calories are consumed when a large portion is served rather than a small one. Thus, steps are warranted for consumers to limit the portion size they take or serve to others , especially foods that are energy dense.
What Is the Relationship Between Portion Size and Energy Intake? • Where? • At home • At school • In restaurants • In fast food outlets • How? • Supersizing • Buy one, get one free • Special sales • Marketing
What is the relationship between the consumption of energy-dense foods and BMI? • “Available data are insufficient to determine the contribution of energy dense foods to unhealthy weight gain and obesity.” • “However, consuming energy dense meals may contribute to excessive caloric intake.” • Conversely, eating foods of low energy density may be a helpful strategy to reduce energy intake when trying to maintain or lose weight.”
What is the relationship between the consumption of energy-dense foods and BMI? • Studies short-term • What is the role of volume? • Role of: • Fat? • Sugar? • Low fiber? • Low water content?
Variety • Generally a good thing • it makes for a better micronutrient mix • But can it lead to overeating? • sensory specific satiety
Availability • Role of availability on dietary choice? • Fruits and vegetables often not available • Fast food widely available • Snacks widely available • Caloric beverages widely available
Cost • Historically, low cost for food in relation to income • price is generally not a strong issue for choice • But, yes, for lower socio-economic groups • gravitate to fast food as cheaper and more plentiful • often pay higher costs for fresh food • How important is cost for leading to poor dietary choices?
What is the Significance of Added Sugars Intake to Human Health? • “Compared with individuals who consume small amounts of foods and beverages that are high in added sugars, those who consume large amounts tend to consume more calories but smaller amounts of micronutrients.” • “Although more research is needed, available prospective studies suggest a positive association between the consumption of sugar-sweetened beverages and weight gain.” • “A reduced intake of added sugars (especially sugar-sweetened beverages) may be helpful in achieving recommended intakes of nutrients and weight control.”
What is the Significance of Added Sugars Intake to Human Health? • Cross-sectional observational studies: • “Most …have found that an increased intake of added sugars is associated with increased total energy intakes.” • Prospective observational studies: • “…found a weak association between the consumption of sugar-sweetened beverages and weight gain.” • Interventional studies: • Few, involving few children, short-term
What is the Significance of Added Sugars Intake to Human Health? • Major sources of added sugars: • Soft drinks (33%) • Cakes and cookies (13%) • Sugars and sweets/candies (16%) • Fruitades/fruit punch (10%) • Breakfast cereals/bars (10%) • Sweetened dairy (9%) USDA/DHHS,2000; Guthrie, Morton, 2000
How Important to Human Health is the Glycemic Response to Carbohydrates? • “Although the use of food with a low glycemic index may reduce postprandial glucose, there is not sufficient evidence of long-term benefit to recommend general use of diets that have a low glycemic index.” • “The inconsistencies among studies are likely due to the poor tools available to measure these dietary components. Food frequency questionnaires can be extremely inaccurate…In addition, the food frequency questionnaires used in these studies were not designed to measure glycemic index or load. The validation data are weak. Prospective, randomized studies are needed…”
What is the evidence to support caloric compensation for liquids versus solid foods? • Is there less compensation for beverages? • Is imposition of strict parental control counterproductive? • How well do children self-regulate if left alone?
Whole Grains and Weight • “There is suggestive evidence from a number of secondary analyses that whole grain intake may protect against weight gain and help with weight maintenance, although the concept that whole grain intake represents a healthy lifestyle cannot be excluded as a confounder.”
Whole Grains and Weight • “There is suggestive evidence from a number of secondary analyses that whole grain intake may protect against weight gain and help with weight maintenance, although the concept that whole grain intake represents a healthy lifestyle cannot be excluded as a confounder.”
Ethanol and Obesity • “Available data on the relationship between alcohol consumption and weight gain/obesity are sparse and inconclusive” • “Although prospective data are limited, there is no apparent association between consuming one or two alcoholic beverages daily and obesity.”
What is the Relationship Between Breakfast Consumption and BMI? • “There is suggestive evidence that eating breakfast is likely to promote healthy weight and improve the nutritional quality of the diet, but more studies are needed before a definitive conclusion can be reached.”
Sedentariness and Nutrient Density • “A sedentary lifestyle limits the amount of calories needed to maintain one’s weight” • “Careful food selection is needed to meet recommended nutrient intakes within this calorie limit” • “Diets that include foods with a high nutrient content relative to calories are helpful in achieving recommended nutrient intakes without excess calories” • “Diets that include a large proportion of foods or beverages that are high in calories but low in nutrients are unlikely to meet recommended intakes for micronutrients and fiber”
Nutrient Density • How can we prevent energy-dense nutrient-poor from displacing nutrient-dense energy-poor foods?
Fruits and Vegetables • “Fruits and vegetables are high in water and fiber content and therefore low in energy density. These types of foods also may promote satiety and decrease energy intake. Therefore, it is plausible to hypothesize that diets rich in fruits and vegetables might prevent weight gain and facilitate weight loss.”
How is physical activity related to body weight? • “Adults: need to make moderate physical activity a part of daily routine for at least 30 minutes per day.” • “Many adults need to participate in up to 60 minutes per day of moderate to vigorous physical activity.” • “Adults who have previously lost weight may need 60 to 90 minutes per day.” • “Children and adolescents need at least 60 minutes per day of moderate to vigorous activity.”
How is physical activity related to body weight? • Reviewed 36 longitudinal studies and 2 intervention studies • Need more intervention studies in both adults and children
Activity and Weight • Is there a level of physical activity below which one cannot regulate weight?
Environment “ In conducting the research on which this report is based, the Committee was struck by the critical and likely predominant role of the environment in determining whether or not individuals consume excess calories, eat a healthful diet, and are physically active.“ “By environment we mean the constellation of cultural forces, societal norms, family influences, changes in meal patterns, and commercial advertising.”
Environment: “environmental influences tend to be beyond the control of individuals” • Large portion sizes served by many food establishments • Lack of information on calorie content at point of purchase • The high amount of sodium in the food supply • The trans-fatty acid content of many ready to eat foods • The cost and availability of fruits and vegetables • Opportunities for safe and enjoyable physical activity
Diet is important to health • Related to a number of major diseases. • Related also to a number of less prevalent diseases. • We need much more public awareness of diet as a preventative of disease. • Awareness needs to be increased, particularly in people who already have risk factors.
Plenty of fruits and vegetables More whole grains Low fat, low sodium foods Less red meat Healthy weight Regular physical activity Moderate alcohol if at all Safe storage and preparation of food Nutrition and Activity Guidelines
Protein15% 8%–10% Saturated fatty acids 10% Polyunsaturated fatty acids 15% Monounsaturated fatty acids Fat30% Carbohydrate 55% Calories: 500–1000 kcal/d reductionCholesterol: <300 mg/dFiber: 20–30 g/d Recommended Nutrient Content of a Weight-Reducing Diet Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults– The Evidence Report. Obes Res 1998;6 (suppl 2).