We should all be aware by now that sugar and highly refined carbs are a huge factor in the epidemic of obesity and that we should be cutting these foods down to an absolute minimum.
For a few, this message to restrict refined carbs has led to ‘carb phobia’ amongst people turning towards more of a Paleo diet, shunning starchy carbs in favour of healthy fats and protein rich foods.
For others it has led to less extreme but positive changes to their carb eating habits: switching to cauliflower based pizza, spiralising courgettes and carrots into ‘spaghetti’, blitzing parsnips into ‘rice’ are all excellent and nutritious replacements for their stodgy white refined alternatives.
I advise my clients to include 2-3 servings a day of starchy carbs, choosing from brown rice, buckwheat noodles, roasted squash and beetroot, quinoa, lentils, chickpeas, new potatoes, sweet potatoes, black beans, flagelot beans, cannelleni beans etc.
These carbs contain resistant starch (RS) – evidence suggests that this type of starch helps to keep blood sugar levels stable and promotes a healthy gut. RS is a type of starch that is not digested in the stomach or small intestine, reaching the colon intact, it literally ‘resists’ digestion.
According to Chris Kresser, there are three main types of resistant starch:
RS Type 1: Starch is physically inaccessible, bound within the fibrous cell walls of plants. This is found in grains, seeds, and legumes.
RS Type 2: Starch with a high amylose content, which is indigestible in the raw state. This is found in potatoes, green (unripe) bananas, and plantains. Cooking these foods causes changes in the starch making it digestible to us, and removing the resistant starch.
RS Type 3: Also called retrograde RS since this type of RS forms after Type 1 or Type 2 RS is cooked and then cooled. These cooked and cooled foods can be reheated at low temperatures and maintain the benefits of RS. Heating at high temperatures will again convert the starch into a form that is digestible to us rather than “feeding” our gut bacteria. Examples include cooked and cooled parboiled rice, cooked and cooled potatoes, and cooked and cooled properly prepared (soaked or sprouted) legumes.
So here are my 5 reasons for making sure Resistant Starch becomes part of your daily diet:
Once RS reaches the large intestine, bacteria attach to and digest, or ferment, the starch. This is when we receive the benefits of RS.
The healthy strains of bacteria in our gut ‘feed’ on RS and produce short chain fatty acids (through fermentation), the most significant of which are acetate, butyrate, and propionate. Of these three short chain fatty acids (SCFA), butyrate is of particular importance due to its beneficial effects on the colon and overall health, and RS appears to increase butyrate production. Butyrate is the preferred energy source of the cells lining the colon, and also plays a number of roles in increasing metabolism, decreasing inflammation and improving stress resistance.
Butyrate acts as a powerful anti-inflammatory agent for the colonic cells, and functions to improve the integrity of our gut by decreasing intestinal permeability and therefore keeping toxins out of the bloodstream.
Several studies have shown that RS may improve insulin sensitivity and decrease blood glucose levels in response to meals.
In one study, consumption of 15 and 30 grams per day of resistant starch showed improved insulin sensitivity in overweight and obese men, equivalent to the improvement that would be expected with weight loss equal to approximately 10% of body weight
RS appears to have several beneficial effects that may contribute to weight loss, including decreased blood insulin spikes after meals, decreased appetite, and decreased fat storage in fat cells.
Resistant starch is also associated with decreased risk of colorectal cancer, thought to occur through several different mechanisms including: protection from DNA damage, favourable changes in gene expression, and the reduction of cancerous or pre-cancerous cells
The adrenal glands, which pump out our stress hormones adrenalin and cortisol, can easily be thrown out of balance by our high pressure lifestyles.
Alan Christianson in his book ‘ The Adrenal Reset Diet’ advises people with adrenal issues to include resistant starch in the diet. Christianson, using his method of ‘carb cycling’, proposes that strategic inclusion of RS helps with weight loss and sleep issues. His theory is that eating resistant starch helps to reduce the demand on the adrenals to produce cortisol thereby keeping blood sugar levels stable and cortisol at a healthy level.
In conclusion, my advice is to include small amounts of starchy carbs in the diet and be selective as to which carbs you are eating, eat small portions of wholegrains, legumes and root vegetables and try including some cooled cooked brown rice and new potatoes a few times a week.