Diets which restrict the types of food consumers can eat in order to promote weight loss may in fact be bad for their health, according to researchers from the University of Arkansas.
Peter Ungar, an anthropologist at the University, said that humans had evolved to consume the widest possible range of foods, and that limiting that variety can lead to serious health risks.
"Americans assume that their diets are varied because of the seemingly infinite array of foods available to us," Ungar said. "But if you look at the average American diet, it consists mainly of fat and starch. Occasionally, we throw in some tomatoes.
"Diets that purport to solve that problem by cutting out entire categories of food are taking the wrong approach," he added. "The modern risk, at least in part, is that our diets aren't varied enough."
Ungar and his colleague Mark Teaford of Johns Hopkins University have just published a book entitled "Human Diet: its Origin and Evolution" which looks at the way human eating habits have developed and changed.
With input from physicians, anthropologists, nutritionists and paleontologists, the book examines human diet from the eating habits of our earliest ancestors to the diet-related health problems that plague our world today. The overall message of the book is clear: human beings evolved to eat the most varied diet of any species and the limited nature of our modern diet can therefore lead to chronic health problems.
Ungar and Teaford suggest that the discrepancy between modern eating habits and the metabolic functioning of the human body has given rise to such diseases as diabetes, cancer and heart disease. Further restriction of food intake, such as that prescribed by fad diets, has been shown to promote kidney failure, enlargement of the pancreas and iron deficiency.
By understanding the diet of Man's earliest ancestors, the researchers hope to identify how modern eating habits have diverged and to assess the physiological consequences of that divergence.
"We are unique in the broad spectrum of foods we take. Primates have a much broader diet than other animals, but we're like super-primates," Ungar explained. "We can eat almost anything we want. That's thanks to our fairly simple gut, our cultural ability to cook and detoxify foods and to our tools, which enable us to break down material that our teeth can't handle."
Nutritional quality has long been inadequate in the modern human diet, but Ungar and Teaford suggest that nutritional variety is also lacking. "As the medical field continues to find links between diet and disease, it becomes evident that the survival of our species may once again hinge on our ability to consume the right foods," Ungar said.