How Dr Atkins brought me to the Genomics Forum

I came to work at the Genomics Forum by a somewhat strange route. As an undergraduate I studied English at the University of Adelaide, South Australia. When the time came to think about a PhD, I was keen to research something more “socially relevant” than literature. I’m not sure I agree with my younger self any longer about the social irrelevance of fiction – or indeed, that “relevant” is even the relevant word. Nonetheless, that wish back in 2003 to study something “relevant” is responsible for my career path to date.

Back in 2003, one of the hottest topics in the media was the craze for the Atkins Diet, and other low-carbohydrate, high-protein weight-loss diets (such as South Beach, Protein Power, and The Zone). Low-carbohydrate diets were hugely popular in the late 1990s and early 2000s in English-speaking countries such as the UK, US and Australia. For those who haven’t tried them, they recommend a more or less drastic reduction in starchy and sugary foods, including bread, rice, pasta and potatoes; all foods with added sugar; and certain high-carb fruits and vegetables (bananas, tropical fruit, sweet potatoes, corn, etc). The rationale is that these foods raise blood sugar and insulin levels, causing weight gain and type 2 diabetes.


My younger self put together a research proposal on low-carbohydrate diet books and took this to Australia’s Commonwealth Scientific & Industrial Research Organisation (CSIRO), Human Nutrition Division. I was lucky enough to receive joint funding and support from CSIRO, though I continued to be enrolled and co-supervised by the English department at the University of Adelaide. As my project progressed, I became especially interested in the evolutionary and genetic explanations for obesity and diabetes that low-carb authors used. I looked in particular at two different but closely related theories: evolutionary nutrition and the thrifty gene theory.

Evolutionary nutrition is a relatively straightforward model, based on the idea that the human body has adapted to function best on the diet eaten in the Paleolithic era. The thrifty gene theory (first proposed by geneticist Dr James Neel in 1962) is more complex. It suggests that feast-or-famine conditions during human evolutionary development naturally selected for people who could store excess energy as body fat for use later on, when food might be scarce. The theory suggests that in today’s circumstances of constant food availability, the so-called thrifty gene predisposes people to obesity and type 2 diabetes. Low-carb diet books use these two models to justify their recommendations, which are supposedly closer to what “our primitive ancestors” ate, and therefore healthier.

For my PhD I looked at the scientific evidence for these theories, as well as their ethical, social and policy implications. I found that representations of Paleolithic diet and human nutritional evolution in bestselling diet books are often inconsistent and lack scientific or historical evidence. For instance, The Zone (Barry Sears, 1995) makes claims about the nutritional breakdown of Paleolithic diets – how much protein, carbohydrate and fat they contained. But these claims are actually contradicted by the same scientific paper that Barry Sears cites in support of his figures.

Similarly, low-carb diet books routinely present the thrifty gene theory as fact. But James Neel only ever proposed the thrifty gene theory as a hypothesis – the evidence for a specific “diabetes gene” or thrifty gene is sketchy at best. Critics from a range of academic disciplines have questioned the evidence for feast-or-famine cycles in prehistoric hunter-gatherer life (the assumption that underpins the thrifty gene theory). These critics point out, too, that it would be impossible either to prove or disprove the thrifty gene theory – since we can’t go back in time.

With my “social relevance” hat on, I was (and am) most concerned with the effects of these theories on how as a society we think about obesity and its causes – especially since these diet books were so incredibly popular. Blanket evolutionary explanations for obesity and diabetes distract attention from national and international inequalities in health and nutrition. Neither obesity nor diabetes is equally distributed within Western societies, or across the globe. Yet this doesn’t rate a mention in low-carbohydrate diet books. Instead, talk of evolutionary and genetic causes for obesity distracts public and policy attention away from the association of overweight and ill-health with poverty and socioeconomic disadvantage.

The end of this story for me personally is that all this thinking and writing about genes, evolution, science and policy got me a job at the Genomics Forum after I finished my PhD. At least I think it did! – maybe the interview panel would say something else. Regardless, 3 years later, the research has finally been published (the wheels of academia turning slowly, as they do!). Read all about it in Public Understanding of Science online.

Christine Knight. “Most people are simply not designed to eat pasta”: evolutionary explanations for obesity in the low-carbohydrate diet movement. Public Understanding of Science, published online ahead of print 10 February 2011 (institutional subscription required to access full text)