The sugar in our blood, glucose, is a bit like Goldilocks; you need just the right amount. Glucose is quite reactive, and high blood sugar can cause serious health problems. Our bodies are normally good at controlling our blood sugar and when our blood sugar rises, insulin is released by the pancreas. The insulin causes our muscles and fat cells to absorb the glucose. The muscles absorb glucose when they are low on Glycogen, turning the glucose to Glycogen for storage. The fat cells turn glucose into fat. If our muscles and fat cells become insulin resistant, then the pancreas may be able to produce more insulin to compensate. If the pancreas cannot compensate, then the blood sugar will be too high and cause diabetes (type 2). High blood sugar causes many problems, including fatigue, depression, weight gain, high blood pressure and increased hunger. There are many factors that contribute to insulin resistance, including genetics, age, smoking, obesity, stress, lack of exercise, diet, and lack of sleep.
A high fact diet without sufficient Omega-3 oils has been linked to insulin resistance. Plant based Omega-3 is not as effective as animal Omega-3, probably because our bodies need the longer animal Omega-3. The shorter plant based Omega-3 can be converted to the longer forms, but the conversion is rather limited. Note that Fructose (table sugar or High Fructose Corn Syrup) is converted by the liver to fats (triglycerides), so it effectively acts as part of a high fat diet. It is also considered possible that both obesity and insulin resistance are caused by persistent overeating of highly palatable foods.
As discussed in Nutrient Timing exercise increases the insulin sensitivity of the muscles. If you take carbohydrate and Protein within 45 minutes of exercise, the insulin sensitivity can be continued for up to 6 hours. There is some evidence of improved insulin sensitivity for up to 24 hours in people suffering from type 2 diabetes after an hour of aerobic exercise.
In addition, there is evidence of long term insulin sensitivity benefits from exercise.
- Invited Review: Effects of acute exercise and exercise training on insulin resistance http://jap.physiology.org/content/93/2/788.full