Low-Carb Diet Lowers Insulin Levels

While not all dietary approaches are applicable or beneficial to everyone, there are some, I think, that generally hold true. Here’s one: If you want a long, healthy life, do what you can to ensure stability of blood sugar and insulin levels.

What this usually means in practice is the regular eating of foods that tend not to disrupt blood sugar (and therefore insulin) levels, such as meat, fish, eggs, green vegetables, certain fruits (for example, apples, berries), beans, lentils, nuts, and seeds.

What this diet is generally devoid of, you may notice, is foods containing refined sugar and starchy carbs such as bread, potatoes, rice, pasta, and breakfast cereals. The primal diet above is often dubbed a low-carb diet on the basis that it contains considerably less carbohydrate compared to the starch-rich diet so often advocated (and eaten) these days. Some people even recommend such a starch-rich diet for diabetics, even though carbohydrate is the specific dietary element that diabetics have difficulty handling.

Part of the rationale for a carb-controlled diet in diabetics comes from the fact that the less carbohydrates one eats, the lower the blood sugar level will tend to be. And at the risk of stating the obvious, this is of clear merit for diabetics whose prime ambition might be to keep blood sugar levels under control.

However, another important part of the rationale for eating a low or lower carbohydrate diet is that it demands less insulin to be secreted by the body’s pancreas. Generally speaking, the less insulin someone secretes, the less likely they are to suffer from insulin resistance (when the body’s ability to respond to insulin’s blood sugar lowering effects is blunted). Also, less insulin means less likelihood that the cells in the pancreas responsible for secreting insulin—the beta cells—will become exhausted.

Basically, the more insulin someone secretes over time, the more likely they are to suffer from a lack of insulin or an inability to respond to it appropriately. This is a situation many type 2 diabetics can find themselves in, particularly, logic dictates, if they eat a diet replete with carbohydrates, including starchy ones.

Of course this concept of controlling carb intake is not just relevant for diabetics, but also for those who would prefer not to develop diabetes. I was therefore interested to read a recent study that tested the effects of low-carb and low fat (and higher-carb) diets in a group of obese adolescents aged 12 to 18. This 12-week long study showed that these diets performed similarly well with regard to changes in measures such as body mass index and body fat percentage.

On the other hand, the low carbohydrate diet out-performed the low fat one in two critical areas. Firstly, insulin levels were lower in those eating a lower-carb diet. The researchers also used an assessment known as the homeostatic model assessment (HOMA), which is used to measure the extent to which an individual is suffering from insulin resistance and beta-cell exhaustion. Here too, the low-carbers faired better.

In short, after just three months on a lower-carb diet, adolescents saw improvements in their biochemistry, which would, generally speaking, put them at reduced risk of developing type 2 diabetes over time. This evidence is in line with other research that has found that the consumption of blood sugar-disruptive carbohydrate is associated with an increased risk of diabetes.

References:

Demol S, et al. Low-carbohydrate (low and high-fat) versus high-carbohydrate, low-fat diets in the treatment of obesity in adolescents. Acta Paediatrica. 2008 Sep 29. [Epub ahead of print]

Dr. John Briffa is a London-based physician and author with an interest in nutrition and natural medicine. Dr. Briffa's Web site

Last Updated Oct 29, 2008