Is Starch Another Form of Sugar?

ruthRuth Buttigieg, BSC (Hons), MSc, ANutr is a qualified nutritionist who works at Natural Ketosis, where she helps people to better their health by changing their diet and lifestyle by following a low sugar low starch approach. Ruth read biochemistry for her undergraduate degree and she also has a Masters in Public Health Nutrition from Queen Margaret University. Here she blogs for us on a question that often comes up when it comes to diabetes and nutrition – is starch another form of sugar?

With the media’s attention on the amount of “added sugar” in our food, the amount of starch consumed daily by the average Briton is not commonly discussed.

A paper published late last year showed that a major contributory factor to obesity in the UK are potatoes and bread [1]. If you are looking to cut sugar out of your diet, it is also worth taking a look at the types of vegetables and fruits you eat, as these may also be contributing to high blood sugar levels.

A common mistake that people make when trying to decrease the amount of sugar in their diet, they overlook items such as starchy vegetables, legumes and grains. While these items look very different to simple sugars such as granulated sugar, honey, etc, they are themselves another form of sugar.

Sugar in all its forms

Simple sugars and starch are digested through the same mechanism in the human body. In the gut, starch is broken down into its simple sugar molecules. These simple sugar molecules (irrelevant of origin before being eaten) are then taken up into the bloodstream causing blood sugar levels to rise. This in turn causes an insulin spike turning excess sugar into the bloodstream as fat as well as preventing the body’s fat-burning capabilities.

Items such as wholemeal bread, legumes and potatoes – so-called white starch – are sometimes deemed to be a good source of sugar, as well as vitamins and minerals. Unfortunately, this is not the case.

Starchy foods will still be turned into simple sugars in the human gut. Ever wondered why you might be struggling to lose those extra few pounds even though you are eating “healthily”? It’s because you are still supplying your body with sugar.

What about Dietary Fibre?

The difference in digestion for dietary fibre is that, due to its chemical structure, it acts as a bulking agent in the gut helping to promote bowel health as well as promoting healthy gut bacteria.

What is a Low Sugar Diet?

A well-formulated, low-sugar diet is one which is not only low in sugar, but also low in starch. To fully get the benefits of this way of eating, you need to ensure that you are consuming the right amount of protein and the right amount of beneficial fats.

It is also important to ensure that you are consuming the right vegetables and fruits in order to get the full benefits of a low-sugar, low-starch diet approach.


1. Kentaro Murakami, Tracy A. McCaffrey and M. Barbara E. Livingstone (2013). Associations of dietary glycaemic index and glycaemic load with food and nutrient intake and general and central obesity in British adults. British Journal of Nutrition, 110, pp 2047-2057.

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