Rates of type II diabetes are rapidly increasing in the United States. However, the disease is almost completely preventable through dietary and lifestyle modification. Here, I will briefly explain how dietary changes interplay with human physiology to produce the type II diabetes epidemic.
Over the last 12,000 years, with the advent of agriculture and cereal grains, carbohydrate consumption has increased radically. Before that time, carbohydrate consumption ranged between 10-125 grams per day. Modern diets today typically have 250-400 grams of carbohydrate.
Equally important, the quality of the carbohydrates most Americans consume today is much different than 12,000 years ago or even 100 years ago. Our pre-agriculture ancestors consumed slowly digesting carbohydrates that were accompanied with large amounts of fiber and other nutrients. A hundred years ago, corn syrup was not a part of the American diet and it now makes up more than 20% of carbohydrate consumption. Today, most Americans consume steady doses of sugar, corn syrup and simple starch all day long, everyday.
A result of this type of diet is an unprecedented increase in type II diabetes. Type II diabetes is a disease in which the body responds inappropriately to insulin. Under normal physiological conditions, our bodies release the hormone insulin after consuming carbohydrates. Insulin causes cells to take up glucose from the bloodstream so that blood glucose levels are normalized. An early stage of type II diabetes is the onset of insulin resistance. In insulin resistant people, insulin is released normally as a result of carbohydrate consumption, but the cells do not appropriately respond to the signal. The body must release more and more insulin to encourage the uptake of glucose from the bloodstream. If dietary modifications are not made, beta cells in the pancreas can become overtaxed and stop making insulin all together. The result is type II diabetes.
Today, insulin resistance is thought of negatively, almost like a disease, because of its association with diabetes and metabolic syndrome. However, it likely developed as a beneficial adaptation that was selected for thousands of years ago. The ice ages that were present for the majority of the last 700,000 years caused carbohydrate scarcity and frequent famines. Because glucose is essential for certain areas of the brain and for developing fetuses, people with insulin resistance had a selective advantage. The insulin resistant state encouraged muscle and liver cells to burn fat for energy, sparing the glucose for where it was needed most. In the case of a pregnant mother, glucose was preserved for fetal development, which allowed insulin resistant mothers to produce healthier babies in times of famine or carbohydrate scarcity.
What was once an advantage has turned into a liability in today’s world of food overabundance. Between 1935 and 1996, prevalence of type II diabetes rose nearly 765%. Between 1996 and 2011, rates of diagnosed diabetes increased another 235%. Overeating and obesity in general is contributing to this trend, but I feel that the over-consumption of quickly digesting carbohydrates is the biggest part of the problem. When one compares the changes in our diet with human physiology, it’s not hard to understand why type II diabetes has become such a huge issue.
The good news is type II diabetes is almost entirely preventable. While there are genetic predispositions for developing type II diabetes, the biggest risk factor is being overweight or obese. Poor diet combined with limited physical activity leads to obesity, accounting for 80-95% of cases of type II diabetes. If one maintains a healthy weight, exercises, and limits consumption of processed carbohydrates, the chances of developing type II diabetes are very low.