What exactly is a low-glycaemic diet?

What exactly is a low-glycaemic diet?

The Harvard Medical School circulated these principles via their online newsletter today. Pretty much the same as a regular, healthy diet, I’d say – except that the first point strikes me as a bit odd.

Why would anyone think tropical fruits have a higher glycaemic index (GI) than any dessert that isn’t fruit? And, if we’re supposed to avoid starchy fruit, why are bananas, the only fruit I’ve ever seen described as ‘starchy’, grouped with mangoes and papayas? And what on earth is a non-starchy bean? As I understand it, all beans contain ‘starch’ though, because this is slowly digested, they’re still low on the glycaemic scale. 

The confusion is hardly life threatening but Harvard Medical School sells itself as providing ‘trusted advice for a healthier life’. It’s also using this list to promote a $30 publication, but I don’t think it inspires a lot of confidence in the brand – or the book!

Eight principles of low-glycemic eating

  1. Eat a lot of non-starchy vegetables, beans, and fruits such as apples, pears, peaches, and berries. Even tropical fruits like bananas, mangoes, and papayas tend to have a lower glycemic index (GI) than typical desserts.
  2. Eat grains in the least-processed state possible: “unbroken,” such as whole-kernel bread, brown rice, and whole barley, millet, and wheat berries; or traditionally processed, such as stone-ground bread, steel-cut oats, and natural granola or muesli breakfast cereals.
  3. Limit white potatoes and refined-grain products, such as white breads and white pasta, to small side dishes.
  4. Limit concentrated sweets — including high-calorie foods with a low glycemic index (GI), such as ice cream — to occasional treats. Reduce fruit juice to no more than one-half cup a day. Completely eliminate sugar-sweetened drinks.
  5. Eat a healthful type of protein, such as beans, fish, or skinless chicken, at most meals.
  6. Choose foods with healthful fats, such as olive oil, nuts (almonds, walnuts, pecans), and avocados, but stick to moderate amounts. Limit saturated fats from dairy and other animal products. Completely eliminate partially hydrogenated fats (trans fats), which are in fast food and many packaged foods.
  7. Have three meals and one or two snacks each day, and don’t skip breakfast.
  8. Eat slowly and stop when full.

The list is Adapted from Ending the Food Fight, by David Ludwig with Suzanne Rostler (Houghton Mifflin, 2008).