Cooked potatoes

Did you know that if you cook a potato, let it cool down, and then re-heat it again, you increase the amount of “resistant starch” found in the potato?

When potatoes are cooled after heating, the starch molecules expand and crystallise, becoming more like dietary fibre. This resistant starch has the same benefits as dietary fibre, it protects against colon cancer, increases the feelings of fullness and may reduce the storage of fat. Resistant starch can’t be broken down, which helps food to move through the system, preventing constipation. And it doesn’t turn back into normal starch if the potatoes are then reheated.

If you eat a potato while it’s still hot from cooking, the structure of the starch has been weakened, which makes it easier for the gut to break down each chain of glucose and therefore absorb it into the blood.

Glucose from cooked starchy foods, such as white rice, pasta and potatoes, is absorbed almost as quickly as glucose from a sugary drink. This means these foods have a high ‘glycaemic index’ or GI.

However, when starchy foods are cooled their structure is reorganised again and the digestive enzymes in your gut can’t break them down so easily. The food now contains more ‘resistant starch’, which is not broken down and essentially becomes fibre.

This explains why the chilled potatoes caused a smaller rise in blood glucose – but what’s even more amazing is that reheated potatoes are even more effective at lowering the rise in blood sugar in comparison to potatoes that have just been cooked. The same applies to pasta and rice just don’t cook them too much, you don’t want a gluggy mess when you reheat them.


Check out this graph;

Graph blood glucose and resistant starch


What are the health benefits of Resistant Starch?

  1. By swapping a meal made with normal starch for one made with ‘resistant starch’ it brings your glucose level down straight away. Over time, high glucose and high insulin levels can contribute to insulin resistance and Type 2 diabetes, so ‘resistant starch’ could be one way to help reduce the risk of Type 2 or reduce the impact of the condition in people who already have it
  2. ‘Resistant starch’ can dramatically increase the fibre content of your diet without affecting the appearance, taste or texture of the food and without you knowing the difference. Foods that have more ‘resistant starch’ can give you the fibre equivalent of brown rice, brown bread or wholemeal pasta without changing your diet. One short-term effect of this is that it helps you feel fuller for longer after a meal.

Cooking method; you can cook them any way you like, boiled and then cut into wedges and fried off (great with a piece of fish), boiled and then roasted, roasted and then re-heated to have jacket potatoes, boiled and then fried as smashed potatoes, boiled, then grated and then cooked as hash browns.

As potatoes are one of the dirty dozen, when it comes to contamination by pesticides, it’s best to buy organic rather than non-organic.

For other foods to avoid from the “Dirty Dozen”, check this out;

Dirty Dozen