A prebiotic can be defined as a “selectively fermented ingredient that allows specific changes both in the gut and/or activity in the gastrointestinal microflora that confers benefits upon host well-being and health” – long story short these little guys improve digestion and nutrient absorption.
Although all prebiotics are fiber, not all fiber is prebiotic. Prebiotic fiber is not digestible by the human body but provides nutrients for the good bacteria we all have living in our gut – these aid in digestion and absorption of the food we consume.
A form of fiber, known as inulin, has been shown to aide in weight loss. Once in the gut, inulin is converted by prebiotic microbes to short-chain fatty acids, which have been shown to produce more appetite-controlling hormones in the body. Acetate, in turn, which is a short-chain fatty acid released when gut microbes digest fiber, then travels from the gut to the hypothalamus where it helps send the signal to stop eating. A study performed on overweight and obese individuals showed a decrease in the hunger hormone, ghrelin, and an increase in the satiety hormone, leptin when 21 grams per day of inulin were consumed. This form of prebiotic fiber can be found in foods such as leeks, asparagus, chicory, Jerusalem artichokes, garlic, and onions.
There are other mechanisms explaining how all fiber, not just prebiotic fibers, can affect satiety. Greater satiation, also known as the feeling of fullness, may be a result of the increased time required to chew certain fiber-rich foods, especially when in comparison to foods lower in fiber, in turn, may slow rate of ingestion and reduce the total amount of food consumed. Additional chewing results in an increased production of saliva and gastric juices which causes gastric distention, or expansion of the stomach allowing for less room in the stomach. This expansion of the stomach is also believed to signal feelings of fullness and satiety to the brain.
Here are some simple food swaps to increase satiety:
- Instead of corn flakes, try swapping for oatmeal
- Rather than drinking apple juice or other fruit juices, try eating the whole fruit
- If you are having an omelet, add some veggies to it
- Swap out a hamburger for a veggie burger
- Instead of rice, try quinoa
- Swap out pretzels for popcorn
- Try greek yogurt topped with berries in place of frozen yogurt
