- Fish raises insulin more than popcorn.
- Cheese raises insulin more than white pasta.
An Insulin Index Of Foods: The Insulin Demand Generated By 1000-kj Portions Of Common Foods, American Journal of Clinical Nutrition, 1997
Among the foods tested, breakfast cereals as a group (Cornflakes, Special K, Honeysmacks, Sustain, All-Bran, muesli, oatmeal porridge) produced a lower insulin score* than protein-rich foods as a group (beef, white fish, cheese, eggs, lentils, baked beans). Foods of equal caloric content were compared.
* Insulin score was calculated as the area under the 120-minute insulin response curve for 1000 kJ of test food, relative to a reference food (white bread). (1000 kJ is about 240 calories.)
A strong insulin response is not always desirable.
The Significance Of Insulin
Insulin is a hormone. It controls the movement of nutrients in the body, notably glucose but also fat and protein. It's an anabolic hormone - one that stores and builds, as opposed to a catabolic hormone - one that breaks down and releases.
Having lots of insulin around, for extended periods of time, can cause problems. Dr. Atkins outlined some of these problems in his 2002 New York Times bestseller, "Dr. Atkins' New Diet Revolution: The Low-Carb Approach That Has Helped Millions Lose Weight And Keep It Off":
- Insulin encourages fat storage and weight gain. "Hyperinsulinism is what makes it hard for many people to lose weight."
- "Insulin increases salt and water retention, a recipe for high blood pressure."
- "Insulin is directly involved in creating atherosclerotic plaques, which, if not controlled, can lead to heart disease."
- "High insulin levels have been shown to correlate with high levels of triglycerides and low levels of "good" HDL cholesterol."
- "High insulin levels correlate with increased risk of breast cancer and polycystic ovarian syndrome. Conversely, the lower levels of insulin, the better the survival rates for breast cancer."
What we eat can influence insulin levels. The assumption (championed by Dr. Atkins and other low-carb proponents) was that carbohydrates caused the greatest relative rise in insulin, and that:
"Insulin secretion [was] largely assumed to be proportional to postprandial glycemia."As you can see from the beginning of this post, the study I cited above did not support those assumptions. Not entirely.
- An Insulin Index Of Foods (See above.)
It did find a correlation between glycemic response and insulin response; that is, if blood sugar went up after eating a specific food, insulin went up proportionately. But that correlation "accounted for only 23% of the variability in insulinemia."
Nutrients other than carbohydrate were found to influence insulin levels. "Fish, beef, chicken, and eggs had larger insulin responses per gram than did many of the foods consisting predominantly of carbohydrate."
Even within food groups there was variability. White bread "consistently produced one of the highest glucose and insulin responses." However, "pasta, oatmeal porridge, and All-Bran cereal produced relatively low insulin responses, despite their high carbohydrate contents."
The authors concluded, "Macronutrient composition of foods has relatively limited power for predicting the extent of postprandial insulinemia."
This knowledge was public when Dr. Atkins revised his bestseller. You have to wonder why it wasn't incorporated.