Resistant Starch: The Healthy Carb for Weight Loss

Starch is basically a nutrient found in carbohydrate-rich foods such as grains, fruits, and vegetables. It is produced by plants and is a major source of calories for humans. It is broken down into glucose during digestion and that glucose is used as energy by the body. However, not all starches are the same. Starches can be divided into three groups:

• Rapidly digestible starch (RDS): It is digested within 20 minutes. Example: mashed potatoes.
• Slowly digestible starch (SDS): It is digested between 20 and 100 minutes. Example: raw starch from wheat.
• Resistant starch (RS): It is not digested but is fermented in the large intestine.
  

What is Resistance Starch?

A resistant starch is any starch that resists enzymes during digestion. Most starches are digested and absorbed into the body by the small intestine. But some starches escape digestion in the small intestine and pass into the colon. There, through fermentation, it is broken down by the resident bacteria releasing short chain fatty acids (SCFA) which act like dietary fiber. This type of starch is called "resistant starch."

Today, thanks to RS, food manufacturers can dream that impossible dream of making several fiber-rich functional foods that are truly appetizing.

What are the types of Resistant Starch?

To date, several categories of Resistant Starch have been identified. Here are the few important ones:

• RS1: It is physically inaccessible starch due to the presence of intact cell walls in grains or seeds. Mainly found in partly milled grains, legumes and seeds.
• RS2: This is the group of the raw uncooked starches. They are further classified in 3 main types:
  • A: Present in most cereal starches
  • B: Present in Green banana and raw potato starches
  • C: Present in most legume starches
• RS3: It is a starch that has been cooked and then cooled and stored for periods of time, ranging from several hours to several months. It is present in cooked and cooled potatoes, cornflakes, bread etc.
• RS4: They do not exist in the nature. They are made by cross bonding with chemical reagents, ethers, esters, etc. (certain modified breads, cakes and pastas).

How does resistant starch help you lose weight?

According a study published in 2004, resistant starch can increase fat oxidation significantly, helping to change the way the body burns fat as fuel. The study found that participants who replaced about 5 percent of their carbohydrates with foods high in resistant starch increased fat burning (the use of fat as fuel instead of carbohydrates) by 23 percent. Over the long term, this could help to significantly reduce the storage of body fat.

Also, resistant starch lowers the caloric content of foods when it is used to replace flour or other rapidly digested carbohydrates. Natural resistant starch is estimated to have approximately 2 calories per gram as opposed to 4.2 calories per gram in completely digestible starch (depending on each individual's metabolism). This is another way that resistant starch can contribute to weight management and weight loss.

What are the benefits of Resistance Starch?

There is substantial research on the health benefits of resistant starches. The Primary benefit is that it acts like fiber during digestion. But that's not it; it also offers many other health benefits including:

• Fiber containing foods are coarser, denser and less appetizing compared to refined, processed foods. Resistant starch enables the incorporation of dietary fiber into refined, processed foods without losing the taste. Thus we get delicious food with significant health benefits.
• Resistant starch lowers the caloric content of foods.
• Resistant starch increases fat oxidation and may lead to lower fat accumulation.
• Foods rich in resistant starch cause slow and steady insulin release, playing a very important role in the insulin response moderation, this way regulating the glucose metabolism. As a result, foods rich in RS are important aid in the body weight management, treatment of obesity, decreasing the risk of developing diabetes as well as other major diseases.
• It also helps decrease adverse effects of hyperglycemia and diabetic complications.
• Prebiotic activity during fermentation promotes the growth of healthy bacteria in the bowel and discourages the growth of potentially harmful bacteria. It promotes a healthy colon and bowel movements.
• Formation of short-chain fatty acids (SCFA), including butyrate and propionate show promise as anti-cancer, anti-inflammatory products.
• Resistant starch is well tolerated and causes significantly less side effects (i.e. bloating, gas).

What foods are high in resistant starch?

Natural sources of resistant starch include:

• Cooked and cooled carbohydrate foods such as cold rice (1/2 cup brown rice - 1.7 gm, 1/2 cup white rice - 0.9 gm), cold potato (1 medium - 1.3 gm) and cold pasta (1 cup - 1.9 gm).
• Unripe fruit such as green banana (1 medium - 4.7 gm).
• Cooked lentils (1/2 cup - 2.5 gm), beans (1/2 cup cooked kidney beans - 2.4 gm), oatmeal (1/2 cup - 0.7 gm).
• Intact wholegrain cereals, seeds and nuts, such as wheat, barley, corn, oats, semolina.
• Wholegrain bread (2 slices - 0.5 gm).

The number of times the procedure of heating the starch and then cooling it again is repeated, the amount of RS goes on increasing. Further, cooking done in microwaves and iron vessels converts more starch into resistant starch than any other method or medium.

How much do I need daily?

Approximately 20 grams a day is recommended to obtain the beneficial health benefits of resistant starch.

Although more research on humans is needed, it is clear that RS posses many health benefits.