Series: Nutrients and Body Health. (Part 2) - Fiber

"Dietary fiber, also known as roughage or bulk, includes the parts of plant foods your body can't digest or absorb. Unlike other food components, such as fats, proteins or carbohydrates — which your body breaks down and absorbs — fiber isn't digested by your body. Instead, it passes relatively intact through your stomach, small intestine and colon and out of your body." 

There are different forms of fiber. 

“Soluble fiber. This type of fiber dissolves in water to form a gel-like material. It can help lower blood cholesterol and glucose levels. Soluble fiber is found in oats, peas, beans, apples, citrus fruits, carrots, barley and psyllium." It also helps lower cholesterol and maintain healthy blood sugar levels. Sources: oatmeal, chia seeds, nuts, beans, lentils, apples, and blueberries.

Insoluble fiber helps push the other foods through the digestive tract. Sources: whole wheat products (especially wheat bran), quinoa, brown rice, legumes, leafy greens like kale, almonds, walnuts, seeds, and fruits with edible skins like pears and apples.

How is fiber beneficial?

It relieves constipation and helps maintain healthy bowels. Fiber relieves pressure from your head when passing a bowel movement.
Fiber gives you energy.
It makes you feel fuller longer. High-fiber foods take longer to digest, which make you feel fuller longer on fewer calories.

Again, fiber gives you energy. Energy gives you resilience to continue.

Source: https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/fiber/art-20043983