Is there a Food Stamp/Obesity Connection ? Summary and Limitations of the Evidence

1. Is there a Food Stamp/Obesity Connection? Summary and Limitations of the Evidence Barbara MkNelly, MS Public Health Institute/Cancer Prevention and Nutrition Section – Department of Health Services – October, 2005

2. Objectives Is Food Stamp Program part of the problem or part of the solution? Summarize current research findings Identify research limitations and knowledge gaps

3. Beware of …….. Numbers which may not “lie” but they don’t tell the whole story

4. Overweight/Obesity – many contributing factors • Individual - Age, ethnicity, genetics, physical/mental health, physical activity • Household - Socio-economic status, cultural practices, social support • Environment – Availability, price, advertising, portion-size

5. Individual - Not everyone is at equal risk - Racial and Ethnic Disparities Overwt/obesity more common in African American and Hispanic children and adolescents. highest among African American and Mexican American women and American-Indian males. Robert Wood Johnson Foundation (2005) A Nation at Risk: Obesity in the United States A Statistical Sourcebook

6. Poverty and Overwt/Obesity can co-exist In some but not all groups, lower incomes are associated with higher prevalence of obesity: Non-Hispanic white teens from lower-income families have a greater prevalence of overweight than those from higher-income families.(Troiano, et al. 1998 NHANES data) Women with income <130%FPL are about 50% more likely to be obese than those with higher income (>130%FPL).(Department of Health and Human Services, Healthy People 2010, 2000)

7. Economics of Obesity “In United States, as food has become cheaper during the past several decades, especially foods high in fat and sugar, obesity rates have risen”. (McCarthy, 2004) Cost per Calorie – healthy food including lean meat, fish, fresh fruits & vegetables (F/V) - costs more than less healthy, high-calorie food with refined grains, added sugars or fats.(Drewnowski et. al.) Statewide survey 46% of lowest-income CA adults agree F/V are “too expensive”. (CDPS, 2002).

8. Why the Focus on Fruits and Vegetables? Eating more fruits and vegetables is associated with the lowest levels of obesity A diet high in F/V is associated with: Feeling full and reduced calorie intake for weight management Lower risks for numerous chronic diseases, including cancer and heart disease. Few adult Americans meet the recommended “5 a Day” Almost 1 in 4 high-income adults (>$50,000) Only 1 in 5 lowest-income adults (<$15,000) (BRFSS, 2003) In 2005, USDA increased the number of F/V recommended in the Dietary Guidelines for Americans.

9. Environment - Disparities in Access to Healthy Food Study of more than 200 neighborhoods found three times as many supermarkets in wealthy neighborhoods as in poor neighborhoods, and four times as many supermarkets in predominantly white neighborhoods as in predominantly African American ones.(Morland, et al., 2002) “..the poor face higher prices due to their greater representation in urban and rural locations –where food prices tend to be higher as opposed to suburbs.”(Leibtag, et al., 2003)

10. Food Insecurity/Obesity Paradox Several studies documented association between food insecurity and overweight among low-income women – but not among men. Possible mechanisms: The need to stretch food dollars to maximize calories. Coping strategy to sacrifice food quality before quantity. Overeating when food is available. Physiological changes – the body compensates for periodic shortages by becoming a more efficiently storing calories as fat.

11. Food Stamp Program and Overweight/Obesity related research Important Difference between…… • Association – things which occur together. • Cause & Effect Relationship– something which influences and changes the other.

12. Criteria for a Cause-Effect Relationship — either “Problem” or “Solution” Time Sequence – “cause” must happen before the “effect”. Plausible mechanism- How did it happen? Consider Alternative explanations. Consistency with other studies.

13. Positive association for girls but not boys • Long-term FSP participation positively related to overweight in young girls • Negatively related to overweight in young boys. • Gibson (2004): national data, multiple observations per child. Controlled for variety of child, family and environmental characteristics, but not food insecurity

14. No association • Lowest income children did not have a higher rate of obesity than higher income children. • No evidence that food programs – FSP, National School Lunch Program and School Breakfast Program – contribute to overweight among poor children. • Hofferth (2005): national data, multiple observations per child. Controlled for variety of child, family and environmental characteristics

15. Preventative association for food insecure girls • Food insecure girls who participated in FSP, School Lunch and School Breakfast had a 68% reduced odds of being at risk of overweight when compared to food insecure girls in nonparticipating households and controlling for other factors. • Boys no difference in overwt if participated in any or all three programs. • Concluded food assistance programs play a protective role for low-income children’s health especially in girls in food insecure households. (Jones, et al, 2003)

16. Adult studies – limited positive association • Positive association between FSP participation and overwt for women - not men. Controlled for variety of individual and family characteristics - but not food insecurity. • Townsend (2001) Cross-sectional study -only 1 measure per individual. • Gibson (2003) Panel study -multiple measures per individual. Current and long-term FSP participation associated with increased risk of obesity of about 2 and 4.5% points.

17. Cause and Effect Criteria –Time Sequence • Overwt/Obesity long-term health outcome • Food Stamp participation often short-term experience. In 1990’s, half of new entrants received benefits for only 8 mos. • No “before” Food Stamp Program measure for comparison.

18. Alternative Explanation - FS participants and income-eligible non-participants show important differences • Many eligible people don’t receive FS • - National participation rate 56% in 2003 • FSP serving the very poor. • Almost 40% of FS households incomes at or below 50% of the poverty level. Only 12% above poverty level. • FS participants more likely to be food insecure than eligible non-participants. Source: USDA 2005 “Making America Stronger: A Profile of the Food Stamp Program”

19. Alternative Explanation - FS participants and income-eligible non-participants show important differences • Many are elderly or disabled. • - 17% of Food Stamp households include an elderly person • - 23% of Food Stamp households include a disabled person • Possibly other differences difficult to measure but also linked to overwt/obesity– depression, childhood trauma. Source: USDA 2005 “Making America Stronger: A Profile of the Food Stamp Program”

20. Food Stamp Program May Simply Reach Women with Certain Characteristics

21. Possible Mechanisms for Positive Association for Women • Purchase of more food with Food Stamps. • Purchase of different foods with Food Stamps. • Townsend “Food Stamp Cycle” hypothesis: • “Abundant food supplies may be available the first 3 weeks of the month, followed by 1 week without food stamps or money when food selection is limited. Then, when money and food stamps restored at the first of the month, food-insecure families may overeat highly palatable and rich foods”

22. Food Expenditures • Food Stamp participant households spent more on food than nonparticipants.(based on 7 studies -Fox et al, 2004) • Estimated increase $2-$4 per person per week. (based on 3 studies -Fox et al, 2004) • For the typical recipient household, $1.00 Food Stamp benefit leads to an increase in household food expenditures of between $0.17-$0.47. (based on 23 studies -Fox et al, 2004)

23. Food Purchasing Patterns • Several studies conclude FSP participation induces households to substitute food at home for food away from home. • One study found spike in food expenditures immediately after monthly benefits but did not find evidence of extreme changes in food energy intake over the monthly benefit cycle. (Wilde et al., 2000)

24. Individual Dietary Intake “Overall, the literature strongly suggests that the FSP has little to no impact on individuals’ dietary intake.” Few studies examined impact on specific food groups or types of foods. Fox et al. (2004) Effects of Food Assistance and Nutrition Programs on Nutrition and Health. Vol 3, Literature Review

25. FSP Participation and dietary intake – USDA review of 26 studies Fox et al. (2004) Effectsof Food Assistance and Nutrition Programs onNutrition and Health. Vol 3, Litrature Review

26. Summary Food Stamp Program is very successful at delivering benefits only to households that need them. FSP participants able to buy more food than would be able to in the absence of the program. Association between FSP and overwt/obesity, Not found for men Inconsistent association for children Positive association for women

27. Summary con’t Timing – studies do not establish cause-effect timing between FSP participation and overwt/obesity. Plausible Mechanism – Little evidence for the “food stamp cycle” or that FSP has impact on individual dietary intake.

28. Summary con’t Alternative Explanations – Complex relationships Food insecurity Other unmeasured factors Opportunity – Even for women, results do not establish FSP participation caused an increase in obesity. But, results suggest FSP offers a way to reach women with a high likelihood of overwt/obesity. (Gibons, 2003)