All-of-government approach needed to tackle obesity

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More and more people are becoming overweight and all over the world. Philip James tells Fiona Fleck how the epidemic started and what should be done to reverse it. Q: What attracted you to the study of obesity? A: After five years working on childhood malnutrition in Jamaica, I came back to the United Kingdom to take over a teaching programme on nutrition and public health at the London School of Hygiene & Tropical Medicine. In 1972, I put in a research proposal to look at why some women increased in weight and got very plump. In response, the Ministry of Health and the Medical Research Council (MRC) asked our department to do a complete analysis of the obesity research literature and this was published as a Department of Health/MRC report in 1976. The MRC thought this was intriguing, as they had never considered funding this area and this led to my being funded to establish the Dunn Clinical Nutrition Centre in Cambridge. Q: Why was that report so important? A: We considered body mass index (BMI) as a standard measurement of overweight and showed that if this went up, your risk of death increased. The Department of Health was concerned because the report suggested that this could become a major public health problem. Q: Where did you find strong enough evidence in this unstudied field? A: We used data that life insurance companies had started gathering before the Second World War in the USA. They had come up with a system of putting extra premiums on people if they were heavy for their sex and height on the basis of the observed life expectancy of the group. They had millions of men and women taking out insurance and provided decades of follow-ups on these individuals. Q: Why did the 1976 report take a BMI of 25 and above for overweight and BMI of 30 and above for obesity? A: We saw from that data that blood pressure went up as the body weight went up from a BMI of about 20 and that at about a BMI of 25--whatever your height or sex--premature mortality started to increase. In the insurance world, the convention was to take obesity to be 20% above normal weight. So, 20% above a BMI of 25 is 30, and so we took a BMI of 30 as the obesity cut-off point. We knew that the BMI was a crude measure and, for example, rugby players might be obese but were stacked with muscle. Nevertheless, we were able to specify the degree of overweight at each level of BMI in the average man and woman. Q: What were the limitations of that study? A: We thought that a BMI of 25 was only useful for estimating the risk of premature death and this has become the criterion for specifying its cut-off point, but now we know that the risk of type 2 diabetes increases rapidly between a BMI of 20 and 25, also the risk of high blood pressure, ischaemic heart disease and some cancers relating to weight gain increase before one's BMI increases above 25. Q: When was obesity classified as a disease? A: It was already classified as a disease when WHO took over the International Classification of Disease in 1948. Subsequently, though, when studying heart disease and high blood pressure, epidemiologists started to classify obesity as a risk factor. They did us a great disservice, as this suggests that risk factors are an individual's responsibility, in this case, for not eating the right foods. That epidemiological approach played a huge role in downplaying the importance of obesity as a public health problem. Q: When did those perceptions change? A: In the mid-1980s, I saw high rates of obesity among women even in poor households in Egypt, Kenya and Mexico, yet these populations were receiving food aid because their babies were stunted. No one was interested in the obesity problem. In 1995, I established the International Obesity Task Force and we contributed to the work of the first WHO expert consultation on obesity. …