What is a resistant starch, and can it help with weight loss? When you eat carbohydrates, they generally come in the form of starches. These foods include common dietary staples like rice, potatoes and beans. Depending on the type of food, the starch is digested in two different ways.
Many starches are digested in the small intestine, and these starches are more readily absorbed by your body and carry a higher caloric count. But some starches do not get digested in the small intestine, and instead make their way into the large intestine – these are called resistant starches.
Starches are made from amylose and amylopectin, which are both a type of polysaccharide. Amylopectin is easily digestible and gives a blood sugar spike (plus an insulin spike). Amylose is much harder to digest, and is found in greater quantities in resistant starches. And amylose-rich starches have lower blood sugar spikes than those heavy in amylopectin. So amylose levels are where the benefits of resistant starches begin.
When a resistant starch enters the large intestine, it is not digested but instead is fermented (& gas is produced, too!) During fermentation, the resistant starch is converted into powerful Short Chain Fatty Acids that include butyrate. But before getting to the benefits of butyrate (and how it can help with weight loss), the resistant starch has already given a great benefit:
Regular starches digest and produce about 4 calories worth of energy for every gram of starch eaten, while resistant starches yield only 2 calories of energy per gram.
If you eat 30 grams worth of regular starch, you are consuming about 120 calories. But if you eat 30 grams of a resistant starch, you are only consuming 60 calories. So if you have the choice between eating a regular starch vs a resistant starch, you can eat the same amount of resistant starch and get only half the calories.
Or you could eat 50 grams of resistant starch and have the same caloric intake as 25 grams of regular starch. So resistant starch let’s you eat more and feel more full as compared to regular starches. So already we’re seeing the weight loss benefits of resistant starch.
Butyrate is an important element of the digestive system. It can also be referred to as Butyric Acid or BTA. It’s found in butter, animal fats, and plant oils. And your body produces butyrate naturally.
Butyrate regulates the growth of cells that line the gut, ensuring that dying cells are stripped away while new cells are being formed. But it gets better.
Butyrate is an anti-inflammatory that is linked to protecting against of some cancers. In this report, patients with Colorectal Cancer were found to have low levels of butyrate in tests, whereas healthy individuals had relatively high levels of butyrate. So keeping butyrate levels in check is a good preventative measure against colorectal cancer. But it still gets better.
In this study, butyrate was shown to increase metabolism in mice. Mice that were fed a butyrate diet saw increased energy (increased heat production) and maintained a lean, consistent weight as compared to a control group. Over the course of 16 weeks, the butyrate mice showed a slight decline in body fat, but the body fat of the control group went UP by over 20%.
So butyrate is a natural metabolism booster! But it all comes from the fermentation that happens with resistant starches. And there are 4 types of resistant starches.