Doctor’s Tip: Insulin and weight gain |

Doctor’s Tip: Insulin and weight gain

Dr. Greg Feinsinger
Doctor's Tip

All the cells in your body use sugar as an energy source. Insulin, a hormone made by the islet cells in the pancreas, can be thought of as the key that allows sugar to enter cells. The pancreas in an optimally healthy person secretes small amounts of insulin after meals to maintain healthy blood sugar levels.

Insulin also has other roles. As Dr. Greger points out in his 2020 book “How Not to Diet,” starches we eat are broken down into simple sugars, proteins we eat are broken down into amino acids, and fats we eat are broken down into fatty acids. These products of digestion are then absorbed into our blood stream.

Insulin causes our cells to take up the amino acids to build new proteins, and — pertinent to today’s column — “stockpiles circulating fatty acids into our fat stores.” Insulin pushes fat into existing fat cells, and also signals fat cells to stop burning calories, all of which contribute to more body fat and to weight gain. The bottom line is that higher-than-normal insulin levels cause weight gain. When type 2 diabetics are started on insulin, they typically gain 7 to 20 pounds from the extra insulin.

Following are some additional factors that cause insulin spikes that — if they occur several times a day, year after year — result in weight gain, prediabetes, diabete, and the complications of diabetes:

INSULIN RESISTANCE: When cells in our organs, muscles and other tissues become clogged with fat, the ability of insulin to allow glucose to enter cells is hampered, resulting in a condition called insulin resistance. The pancreas tries to compensate for this resistance by producing more and more insulin over the years, resulting in abnormally high levels of insulin. This in turn causes cells to store more fat, resulting in weight gain, which causes even more insulin resistance — so a vicious cycle ensues. Eventually, the pancreas wears out and diabetes is diagnosed. Insulin resistance should be diagnosed and reversed at an early stage — signs are extra weight around the middle, high triglycerides and low HDL (good cholesterol), and borderline to mildly elevated fasting blood sugar and/or A1C (a blood test indicating the average blood sugar for the previous three months).

FATTY FOOD raises insulin levels. Even one high-fat meal results in a 50 percent increase in insulin resistance. Dr. Greger notes that “saturated fats concentrated in meat, dairy and junk food can create the toxic breakdown products in our muscle cells thought responsible for the development of insulin resistance.”

ANIMAL PROTEIN, INCLUDING POULTRY AND SEAFOOD increases insulin surges. In general, “meat consumption is associated with increased insulin levels, weight gain and higher diabetes risk, and substituting in even just 5 percent of plant protein for animal protein may decrease diabetes risk by 23 percent.”

GLYCEMIC INDEX: If you eat a whole fruit such as an orange, the sugar is absorbed into your blood stream slowly, due to the fiber in the orange. We call that a low glycemic index food because it doesn’t cause insulin spikes. Orange juice, however, immediately raises blood sugar, and therefore causes insulin spikes. Other examples of other foods with a low glycemic index are: beans, chickpeas, split peas, lentils, whole grain bread with a total carb:fiber ratio of 5:1 or less. Other examples of high glycemic index foods are most cereals that come in a box, dates, white rice, white potatoes and raisins.

In summary, if you want to lose weight avoid foods with a high glycemic index, avoid fatty foods, and chose plant over animal protein.

Greg Feinsinger, M.D., is a retired family physician with a special interest in heart disease and diabetes prevention and reversal, ideally though lifestyle changes. He’s available for free, one-hour consultations — call 970-379-5718.

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