What is a resistant starch?
Resistant Starches (RS) are referring to carbohydrates (starches) that are not digested by your small intestine because they are resistant to digestive enzymes in the human body. This is how they coined the name "resistant" starches. However, once they reach the colon they can be digested by bacteria which feeds the good bacteria (short chain fatty acids) in your colon. This effect is one reason why we want to eat resistant starches. Another interesting fact about resistant starches is that they have less carbohydrates and calories than regular starches which can help with weight loss and insulin sensitivity.
Here's the technical info: There are 5 types of resistant starches
The main resistant starches that we come across are type 1, 2 & 3. Type 1 & 2 are naturally occurring in grains, veggies, beans, nuts and potatoes, these are what you will see on food labels when they list "fiber". Type 3 we can make ourselves by the way we cook our foods.
How to make type 3:
If you take a potato, rice, pasta or squash and cook it then allow it to cool it will form cell walls that can not be broken down by enzymes. This is called starch degradation (1). In addition, it will contain about 25% less carbs and calories than the original heated version. You can reheat the food again before eating it and it will still have the resistant starches. Resistant Starches are 2 calories per gram , regular carbohydrates are 4 calories per gram. You can get the same food volume at less calories which is great for keeping yourself full especially when at a caloric deficit for weight loss. If you are a performance athlete or need to gain weight keep in mind when eating Resistant Starches that you can't count all of those carbs towards your daily intake.
What are the health benefits of eating resistant starches? (hang on for some science...)
As I mentioned previously RS (resistant starches) feed the short chain fatty acids (SCFA) in your colon aka "good bacteria". There are primary & secondary degraders which have enzymes that break down RS. The primary are:
Glucose- Make acetate & formate (gases used by other bacteria living in the colon)
Lactate - Feed anaerobic bacteria
Methanogens Gas (methane) - that's why eating too many resistant starches can cause gas, cramping and bloating. 30-45g a day max is ideal. ***
They then change to the secondary degraders :
Butyrate - Main form of energy for colon cells and does not go into the bloodstream (butter is a popular form of butyrate)
Acetate- Can result in lipogenesis (using fat for fuel) and is used in cholesterol synthesis which lowers cholesterol levels
Propionate- Used by the liver and for gluconeogenesis (process by which our body uses protein for energy)
**95% of Acetate and Propionate is absorbed through the colon & lumen and 5% is exerted through feces.
Hmmmm ok what's this mean for me?
1. Aids in digestion of your food
2. Help you feel full longer
3. Feed the good bacteria in your colon
4. Allow more volume of food with less calories
5. Can aid in lowering cholesterol
6. Can reduce insulin resistance (diabetes)
7. Can aid in weight loss and lowering obesity (2)
What foods can I eat to consume more resistant starches?
1. Chickpeas, beans, lentils, raw potatoes (all types), pumpernickel bread, sourdough bread, green banana.
2. Cooking potatoes, pasta, oats or rice and allowing them to cool 12 hours before reheating them to eat again. Many of use who meal prep in advance have been doing this process without even realizing it.
**Yet another reason why prepping your meals in advance can help with weight loss and overall nutritional health!