Obesity is running rampant throughout the western world. More than 1 in every 3 Americans and every 1 in 4 Canadians is obese. Obesity is not just a problem of being large. It is associated with a variety of other health concerns including heart disease, stroke, cancer, and type-2 diabetes. These are all some of the leading causes of preventable death. A simple change in diet and the addition of exercise is often enough to reduce the burden of suffering in these people. Unfortunately, food and drinks portions are getting bigger, absurd foods (a burger where the bun is a donut) are popping up everywhere, and people are becoming more sedentary. This is not only leading to a rise in obesity rates, but also a rise in the rates of type-2 diabetes. Type 2 diabetes affects over 29 million Americans (1 in every 10) and over 2 million Canadians (1 in every 20). It is caused by a loss in the ability of your body to take glucose into its cells. Cells normally do this by respond to insulin circulating in your blood. Insulin is released when you eat a meal and it helps you store away glucose for use at a later time. When insulin doesn’t work, the glucose collects in your blood and can cause nerve damage, cardiovascular disease, kidney damage, and a host of other problems. There is a very strong link between obesity and type-2 diabetes but it is still unknown exactly how they are linked. Research out of Philadelphia using healthy male volunteers may have hinted at that missing link.
In this study 6 healthy males were overfed food for 1 week and were told not to perform any physical activity. The diet they were fed consisted of typical US diet with around 6000 calories per day. The average active male only needs around 2400 calories a day. The men in this study gained 3.5kg/7.7 pounds after the week of the heavy caloric diet and had signs of resistance to insulin after 2-3 days. This meant these men had signs of early type-2 diabetes after over eating for only a week. In addition to the changes in weight and insulin sensitivity, the men had a large increase in the amount of oxidative stress in their body. You may not know what oxidative stress is but surely you have heard about anti-oxidants. They are found in large quantities in the fruits and veggies we should be eating. Anti-oxidants counteract oxidants. Oxidants damage our tissues and contribute to what is known as oxidative stress. The more oxidative stress you have the more damage being done to your tissues. The more anti-oxidants you have, the more protected you are from oxidative stress.
So what is the new finding in this research? We already know that over eating causes weight gain and insulin resistance. Well the researchers identified a protein on the fat cells of these men that is irreversibly damaged by the oxidative stress in a process known as carbonylation. This carbonylation renders the protein ineffective. In the case of this experiment, the protein that was damaged and rendered ineffective was known as GLUT4 (Glucose transporter type 4). This protein is important in taking glucose from the blood into the cells for storage. If it doesn’t work then glucose remains in the blood. Eureka! When people over eat they gain weight and have an excessive amount of oxidative stress. This oxidative stress damages proteins, one of which is GLUT4. When GLUT4 doesn’t work glucose isn’t taken up into the cells and you end up with high blood sugar and type-2 diabetes.
This research is interesting and begins to answer some questions that researchers have about obesity and diabetes. It was a relatively small study so more work will need to be done before we close the case on the obesity diabetes link. In the mean time if you are over weight then chances are you may be on your way to type-2 diabetes. Get checked by your doctor, get active, and eat healthy.
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