Fighting youth body fatness: The role of food prices
Michael Grossman, Erdal Tekin, Roy Wada, 28 September 2013
- Since the mid-1970s, the proportion of children aged 12 to 19 who are obese has more than tripled from 5.0% to 18.1% in the US (Ogden et al. 2010).
- Childhood obesity has been associated with a host of chronic health problems, such as high blood pressure, hypertension, gallbladder disease, and Type 2 diabetes as early as adolescence (Serdula et al. 1993; Freedman et al. 1999; 2007; Hill, Catenacci, and Wyatt 2006).
Why the extra weight?
- Falling food prices.
- Increased demand for sugary drinks.
- Advertising of unhealthy foods targeted at children.
- Increased time spent in sedentary activities, such as watching TV or videos, using a computer, or playing computer games.
- Lack of vigorous physical activity.
- Increased food-portion sizes.
- In general, empirical studies that examined the effects of prices on obesity found stronger effects than studies that examined the effects of food taxes (Powell, Chriqui, and Chaloupka 2009; Fletcher, Frisvold, and Tefft 2010).1
- There is also reasonably consistent evidence demonstrating that fruit and vegetable prices, particularly of the non-starch variety, are associated with lower weight outcomes while fast-food prices are associated with higher weight outcomes for the adolescent population (Powell et al. 2013).
Problems with the BMI as an indicator of obesity
- It is argued that some of the weak or mixed results documented by studies using BMI may be due to its limited ability to correctly distinguish body fat from lean body mass (e.g., Yusuf et al. 2004, 2005; Romero-Corral et al. 2006, 2007).
- Increases in the real price of one calorie of food for home consumption and the real price of fast-food restaurant food result in significant reductions in the in PBF among youths.
- An increase in the real price of fruits and vegetables has negative consequences for these outcomes.
- Measures of PBF derived from BIA and DXA are no less sensitive and in some cases more sensitive to the food prices just mentioned than BMI, and serve an important role in demonstrating that rising food prices (except for those of fruits and vegetables) are associated with reductions in obesity rather than in body-size proportions alone.
- We show that selective taxes or subsidies may be able to accomplish part of this goal through changes in food prices.
- It should be kept in mind that taxes are blunt instruments that impose significant welfare costs on individuals who consume food in moderation.