Sahasporn Paeratakul

Fast-food consumption among US adults and children: dietary and nutrient intake profile.

OBJECTIVE To examine the dietary profile associated with fast-food use. To compare the dietary intake of individuals on the day that they ate fast food with the day that fast food was not eaten. DESIGN Cross-sectional study design. The dietary intake of individuals who reported eating fast food on one or both survey days was compared with those who did not report eating fast food. Among the individuals who reported eating fast food, dietary intake on the day when fast food was eaten was compared with the day when fast food was not eaten. Weighted comparison of mean intakes and pairwise t-test were used in the statistical analysis. Subjects/setting Data from 17370 adults and children who participated in the 1994-1996 and 1998 Continuing Survey of Food Intakes by Individuals. Dietary intake data were collected by 2 non-consecutive 24-hour dietary recalls. RESULTS Fast-food use was reported by 37% of the adults and 42% of the children. Adults and children who reported eating fast food had higher intake of energy, fat, saturated fat, sodium, carbonated soft drink, and lower intake of vitamins A and C, milk, fruits and vegetables than those who did not reported eating fast food (P<.001). Similar differences were observed among individuals between the day when fast food was eaten and the day when fast food was not eaten. CONCLUSIONS Consumers should be aware that consumption of high-fat fast food may contribute to higher energy and fat intake, and lower intake of healthful nutrients.

The relation of gender, race and socioeconomic status to obesity and obesity comorbidities in a sample of US adults

OBJECTIVE: To examine the obesity-related chronic diseases in the US adult population according to gender, race and socioeconomic status.METHODS: Data from the 1994–1996 Continuing Survey of Food Intakes by Individuals (1994–1996 CSFII) conducted by the US Department of Agriculture/Agricultural Research Service (USDA/ARS) were used in the analysis. Relevant data included self-reported weight and height, self-reported physician-diagnosed diabetes mellitus, hypertension, heart disease and high serum cholesterol. Analysis was conducted according to gender, race, income level and education level.RESULTS: There was a graded increase in diabetes, hypertension and high serum cholesterol with increasing body weight in nearly all gender, racial and socioeconomic groups. Among the obese individuals, the prevalence of hypertension was higher in black subjects and the prevalence of diabetes, hypertension and heart disease was higher in individuals with lower education compared to their counterparts. The odds of having diabetes, hypertension, heart disease and high serum cholesterol increased with increasing body weight after adjusting for age, gender, race, income, education and smoking.CONCLUSION: Although cross-sectional in nature, our results suggest that the disease burden associated with obesity in the population may be substantial. This burden increases with increasing severity of obesity. Our findings support the current opinion that, although the nature of obesity-related health risks is similar in all populations, the specific level of risk associated with a given level of obesity may be different depending on gender, race and socioeconomic condition.

Dietary fat and obesity: a review of animal, clinical and epidemiological studies

The First Law of Thermodynamics provides a framework for understanding the imbalance between energy intake and expenditure that produces obesity, but it does not help understand the role of genetics, the regulation of food intake, the distribution of body fat, the mechanisms by which diets work or the mechanism by which portion control has gotten out of control. In animals, increasing dietary fat increases body fat, and it is unlikely that humans escape this important biological rule. In epidemiological studies, increasing dietary fat is associated with increased prevalence of obesity probably by increasing the intake of energy dense foods. In the National Weight Loss Registry, three things were associated with weight loss: continued monitoring of food intake, lowering dietary fat intake, and increased exercise. The relation of dietary fat is most evident when physical activity is low. The speed of adaptation to dietary fat is increased by exercise. When dietary fat is reduced, weight is lost, but weight loss eventually plateaus. The rate of weight loss during the initial phase is about 1.6 g/day for each 1% decrease in fat intake. When dietary fat is replaced with olestra to reduce fat intake from 33% to 25% in obese men, weight loss continues for about 9 months reaching a maximum of nearly 6% of body weight and a loss of 18% of initial body fat. In the control group with a 25% reduced-fat diet, weight loss stopped after 3 months and was regained over the next 6 months, indicating the difficulty of adhering to a conventional low-fat diet. Thus, dietary fat is an important contributor to obesity in some people.

Healthy Eating Index and obesity

Background: There is a continuing need to examine the relationship between diet quality and health in the population. The Healthy Eating Index (HEI) has been developed as a composite measure of diet quality by the US Department of Agriculture.Objectives: The first objective was to use the HEI to assess the diet quality of a representative sample of the US population and population groups. The second objective was to examine the association between HEI and obesity.Design: Cross-sectional analysis of data from 10 930 adults who participated in the Third National Health and Nutrition Examination Survey. Sociodemographic, physical activity, dietary, and health data were used in the analysis. Diet quality was assessed with the HEI score, ranging from 0 to 100, based on 10 dietary criteria. A low HEI score indicates poor diet.Results: A majority of survey participants had a low HEI score. The percentage of individuals classified as having a poor diet varied by age, gender, race/ethnicity, income, and education. A low HEI score was associated with overweight and obesity. There was a graded increase in the odds ratio of obesity across the HEI category after adjusting for age, gender, race/ethnicity, physical activity, smoking, alcohol use, income, and education.Conclusions: An index of diet quality, such as HEI, may provide a comprehensive assessment of diet in the population. Since the HEI is based on the US Dietary Guidelines, the use of these guidelines as a way to improve health should be emphasized. However, the overall effectiveness of these guidelines in disease prevention needs to be studied further.Sponsorship: None.

Changes in diet and physical activity affect the body mass index of Chinese adults

OBJECTIVE: To examine the relationship between diet, particularly dietary fat intake, and body mass index (BMI).DESIGN: Prospective study of adults who participated in the 1989 and 1991 China Health and Nutrition Survey.SUBJECTS: 3484 adults aged 20–45 at baseline (1989) survey.MEASUREMENTS: Measurement of dietary intake with replicated 24 h dietary recalls. Anthropometric measurements. Measurements of physical activity, smoking habit and socio-economic factors.RESULTS: Change in fat intake was positively associated with change in BMI in men (β=0.00036, P=0.0001), and change in physical activity level was inversely associated with change in BMI in women (β=−0.12, P=0.02). Energy intake, physical activity and major socio-economic factors were related to BMI in cross-sectional analysis.CONCLUSIONS: Diet is becoming an increasingly important determinant of body weight in this population, where fat and energy consumption has been increasing steadily during the past decade.

Body weight patterns among the Chinese: results from the 1989 and 1991 China Health and Nutrition Surveys.

OBJECTIVES A longitudinal survey assessed the distribution of adult body weight among the Chinese population. METHODS Data from the 1989 and 1991 China Health and Nutrition Survey were used to study changes in the proportions of adults aged 20-45 years who were classified as underweight, normal weight, overweight, and severely overweight. RESULTS There was a slight decline in the proportion of men and women classified as underweight, but among lower-income persons an increase occurred. The proportion of adults with normal body weight decreased, and the proportions of those classified as overweight and severely overweight increased during the same period. The observed increases in proportions of adults classified as overweight and severely overweight were largely confined to the urban residents and to those in the middle- and high-income groups. CONCLUSIONS Results indicate increases in both obesity and undernutrition. Current efforts in China to develop a preventive health care policy emphasize the prevention of excess nutrient intakes and overnutrition and, hence, address the problem of the increase in obesity among well-to-do, mostly urban residents. However, the increase in undernutrition among low-income Chinese adults should not be overlooked and requires further research and serious policy consideration.

Measurement error in dietary data: implications for the epidemiologic study of the diet-disease relationship.

Objectives: To examine the effect of measurement error in dietary data on the relationship between diet and body mass index (BMI). To correct for the effect of measurement error on diet–BMI association by using replicate measurements of diet. The effect of measurement error on diet–BMI relationship was simulated, and its implications are discussed.Design: Prospective study design.Setting: The first and second China Health and Nutrition Survey conducted in 1989 and 1991, respectively.Subjects: Three thousand, four hundred and seventy-nine adults age 20–45 y at the 1989 survey.Methods: Statistical methods were used to demonstrate the effect of measurement error in dietary data on the diet-BMI association.Results: By using the average of three replicate 24 h dietary recalls, the attenuation of diet-BMI association was reduced substantially. The regression coefficients of fat and energy intakes differed markedly from those computed by using only single measurement of diet.Conclusions: Measurement error in dietary data may significantly attenuate the diet-disease association. Where appropriate, specific emphasis may be needed to address the problem of measurement error in the study of diet-disease relationship.Spnosorship: This research was supported by the National Institute of Health, the Carolina Population Center and the Nutrition Institute, University of North Carolina at Chapel Hill.

Sex difference in measures of body fatness and the possible difference in the effect of dietary fat on body fatness in men and women.

Objectives: To examine the sex difference in anthropometric measures of body fatness and to explore the possibility that diet may have differential effects on body fatness in men and women.Design: Prospective study design.Setting: The first and second China Health and Nutrition Survey conducted in 1989 and 1991, respectively.Subjects: 1449 men and 1683 women age 20–35 y at the baseline (1989) survey.Methods: Anthropometric measures of body fatness in men and women were compared. Statistical methods were used to explore the potential difference in the effect of dietary fat on body fatness in men and women.Results: Measures of body fatness, especially peripheral fatness, differed markedly between men and women in this study sample. Statistical analysis suggested that the effect of dietary fat on body fatness may be different in men compared to women.Conclusions: Sexual dimorphism in body fatness has important implications for both clinical and epidemiologic research of obesity. The possibility that diet may have differential effect on body fatness in men and women needs to be investigated.Sponsorship: This research was supported by the National Institute of Health, the Carolina Population Center and the Nutrition Institute, University of North Carolina at Chapel Hill.

Current Theories Regarding the Influence of Diet and the Control of Obesity

Current theories regarding the role of diet in human obesity have evolved around the macronutrient composition of diet and its effect on weight maintenance. Obesity is the result of long-term positive energy balance caused by intake exceeding expenditure. Fat, protein, and carbohydrate contribute to the total energy intake. Of these, dietary fat is the one most strongly implicated in the development of obesity. In this chapter, we review the role of dietary macronutrient composition, particularly dietary fat content, in the regulation of food intake and body weight. Understanding this role is necessary for answering two important questions: (1) Is the reduction in energy intake through a decrease in fat intake effective in reducing the very high prevalence of obesity in industrialized countries where diet is usually high in fat? (2) Can obesity be prevented in the populations where diet is traditionally low in fat by stopping the progression toward a high-fat diet?