Promotion of healthy urban transport policies, such as walking and cycling, would help reduce both world oil demand and global food insecurity -- not only through less car use overall, but by reducing the excess demands on food and car use from the obese part of the population. The issues are discussed in this week's edition of the Lancet by Dr Phil Edwards and Dr Ian Roberts, London School of Hygiene and Tropical Medicine, UK.
The authors say: "Motorised transport is more than 95% oil dependent and accounts for almost half of world oil use. Because oil is a key agricultural input, demand for transportation fuel affects food prices. Increased car use also contributes to rising food prices by promoting obesity, which, for the reasons outlined below, increases the global demand for food."
The authors estimate* that a population with a stable mean body-mass index (BMI) of 24.5kg/m2 consumes an average of 1550 calories of food per person per day (pppd) to maintain the basal metabolic rate (BMR) and a further 950 calories pppd for activities of daily living -- a total of 2500 calories pppd. An obese population of 1 billion people with a stable mean BMI of 29.0 kg/m2 would require 1680 calories pppd to maintain BMR and 1280 calories pppd for activities of daily living. Compared with the normal population, the obese population consumes 18% more food energy.
Additionally, more transportation fuel energy will be used to transport the increased mass of the obese population, which will increase further if, as is likely, the overweight people in response to their increased body mass choose to walk less and drive more.
The authors call for transport policies that promote walking and cycling to reduce obesity in the population, and to reduce transportation oil demand. Reducing the prevalence of obesity would, they say, reduce the global demand for both fuel and food. They conclude: "Decreased car use would reduce greenhouse gas emissions and thus the need for biofuels, and increased physical activity levels would reduce injury risk and air pollution, improving population health."
Notes to editors: *full details of the calculations are available from the authors via the contact details below
For further information, or to interview Ian Roberts or Phil Edwards, please contact the London School of Hygiene & Tropical Medicine Press Office on 020 7927 2073/2802 or email firstname.lastname@example.org