Fiber: A Fat-blasting Superfood?
Search the web for “superfoods” and you will come across hundreds of articles about chia seeds, acai berries, coconut oil, quinoa, dark chocolate, and more...but I bet you won’t see fiber on any of these lists. However, if you are looking to target abdominal fat, those expensive “superfoods” probably won’t help you as much as good old dietary fiber.
Soluble vs insoluble
You probably know what fiber is and generally what types of food it is found in (think plant foods), but did you know that there are two types of fiber? Fiber is found in whole fruits, vegetables and grains, and it is either soluble or insoluble.
Soluble fiber dissolves and can be digested more easily (think oatmeal or beans), whereas insoluble fiber is the tough cellulose (think celery strands) that passes through our digestive tract. Fun fact: cows have multiple stomachs in order to be able to break down and digest cellulose for energy, since a majority of their diet is rough plant material. Humans can’t digest these insoluble fibers completely.
Both types of fiber are good for us for different reasons. Insoluble fiber helps keep us regular, feel more full, and keep our intestines healthy. Soluble fiber is actually crucial to our body’s ability to package and remove sugar, cholesterol and fat from our bloodstream, and this is one way in which scientists think that fiber directly helps to lower belly fat.
Studies have shown that people who consume more fiber have lower amounts of visceral stomach fat. Visceral fat is a particularly bad type of body fat that is metabolically active, meaning it releases it’s own hormones and interferes with the way our body utilizes insulin. High amounts of visceral fat are linked with type 2 diabetes and heart disease.
How much do we need?
Many recent studies have shown that increasing dietary fiber, without making any other dietary changes, can result in weight loss. So how much is enough? Women should consume 25 grams per day, and men should consume 38 grams per day. If you are over the age of 51, you need slightly less: 21 grams for women, and 30 grams for men. The average American currently consumes about 15 grams per day - far short of the recommended amount.
What are the best sources?
Focusing on consuming whole fruits and vegetables is your best bet, as these come packaged with both soluble and insoluble fiber.
Aiming for 2 servings of fruit and at LEAST 3 servings of vegetables each day is a good starting goal. (Follow this link for a nice explanation of what a serving size is for different foods). Here are a few great sources of fiber to try and add to your daily diet!
- 1 large pear with skin (7 grams)
- 1 cup fresh raspberries (8 grams)
- ½ medium avocado (5 grams)
- 1 ounce almonds (3.5 grams)
- ½ cup cooked black beans (7.5 grams)
- 3 cups air-popped popcorn (3.6 grams)
- 1 cup cooked pearled barley (6 grams)
And here is an example menu that shows how to make menu swaps to increase your fiber over the course of a day.
Resources:
http://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/high-fiber-foods/art-20050948 - MayoClinic list of high fiber foods
http://jn.nutrition.org/content/130/2/272S.full - Fiber and Energy Regulation
http://www.health.harvard.edu/blog/making-one-change-getting-fiber-can-help-weight-loss-201502177721 - Fiber and weight loss study
