In healthy people if blood glucose is normal then insulin is usually normal. For those with insulin resistance, insulin levels are higher than expected relative to glucose, with blood sugar and insulin levels remaining high long after eating.
Insulin is the hormone that is released from the pancreas and acts as a chaperon helping glucose in the blood to enter the cell tissue where it signals the liver to store glycogen and the fat cells to store energy. It helps control your bodies blood sugar levels and metabolism.
In insulin-sensitive healthy individuals only small amounts of insulin are required to encourage glucose to enter cells.
Insulin resistance causes the cells to become less sensitive to insulin. This results in impaired blood glucose uptake in the cells, high blood glucose levels in the blood, increased release of glucose from the liver, and increased levels of fatty acids in the blood. To compensate, the beta cells of the pancreas release more insulin leading to higher insulin levels, which causes increased fat storage and weight gain. Eventually the pancreas does not make enough insulin, or the cells become resistant, glucose builds up in the bloodstream, leaving the cells starved for energy. Eventually the pancreas cannot make enough insulin, or the cells can’t properly use the insulin the pancreas makes (1).
In obese individuals’ high insulin leads to leptin resistance making it harder to feel full.
Prediabetes is a state of insulin resistance. In Type 2 diabetes insulin resistance has progressed to the point where the body is unable to keep blood glucose in check. Excessive insulin responses to sugar are associated with other chronic metabolic diseases including, obesity, cardiovascular disease, cancer, and Alzheimer’s (2).
Insulin resistance can creep up on us and often takes several years before an individual has symptoms or is diagnosed. Although blood glucose and insulin are both important measurements, insulin is the better indicator of disease and can sometimes alert us to a problem such as Type 2 Diabetes, 20 years before diagnosis (3).
Food is the major cause of spiking blood sugar however there are other things which over time can lead to insulin resistance as well. Disturbed sleep can cause blood glucose spikes and these same spikes can lead to further poor sleep. Long term stress can cause glucose levels to rise, and spiking blood sugar influences our stress glands, the adrenals. Caffeine raises cortisol which can cause a spike in blood sugar. Chronic inflammation can lead to elevated insulin levels as well (4).
Insulin resistance, obesity and type 2 diabetes are common consequences of the modern world we live in with increased sedentary lifestyles and increased energy dense diets. Insulin resistance with obesity and diabetes is a worldwide epidemic (5).
Things we can do to combat insulin resistance include avoiding all processed, junk or packaged foods, stopping the eating of refined sugars and carbohydrates, eating plenty of soluble fibre, having lots of healthy fats in the diet, getting 8 hours of good quality sleep, increasing exercise, and finding ways to reduce stress.
Putting the right lifestyle habits into place combined with a healthy diet are essential for reversing insulin resistance. Using your food as medicine, you can improve your insulin sensitivity and make your blood glucose noticeably easier to control while decreasing the risks to disease.
Life is full of highs and lows we cannot always control, but we can influence our blood glucose levels, avoid the sugar roller coaster which will lead to significant positive healthy outcomes.
- Cavaghan M.K, Ehrmann D.A, and Polonsky K.S. Interactions between insulin resistance and insulin secretion in the development of glucose intolerance.The Journal of Clinical Investigation, 2000; 106 (3): 329–33.
- Ferreira L.S.S, Fernandes C.S, Vieira M.N.N , De Felice F.G. Insulin Resistance in Alzheimer’s Disease.Frontiers in Neuroscience, 2018; 12: 830. DOI: 10.3389/fnins.2018.00830
- Sagesaka H, Sato Y, Someya Y, Tamura Y, Shimodaira M, Miyakoshi T, Hirabayashi K, Koike H, Yamashita K, Watada H, Aizawa T. Type 2 Diabetes: When Does It Start? Journal of the Endocrine Society.2018; 2 (5): 476–484. doi: 10.1210/js.2018-00071
- Mesarwi O, Polak J, Jun J, and Polotsky V.Y. Sleep disorders and the development of insulin resistance and obesity. Endocrinol Metab Clin North Am, 2013; 42 (3): 617–634.doi: 10.1016/j.ecl.2013.05.001
- Seidell JC. Obesity, insulin resistance and diabetes–a worldwide epidemic. British Journal of Nutrition, 2000; 83 (S1): S5-S8. DOI: https://doi.org/10.1017/S000711450000088X