Welcome back to Thank God It’s Monday!
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​tl;dr Everything you ever wanted to know (and more) about fiber: how it keeps you regular, full, and (colorectal) cancer-free.

What is fiber?
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​Fiber is the indigestible part of plant foods (we cannot break it down). It moves through our digestive tract, kicking ass and taking names. Just kidding. But it does have many important roles. It supports beneficial gut bacteria associated with immune function, mood, and metabolism. It slows glucose absorption and can help prevent type 2 diabetes. It binds to LDL (“bad cholesterol”) to show it the door (bye felicia) before it enters the bloodstream. In addition to slowing digestion, which increases our satiety, making us feel full for longer.
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​How much do we need?
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​Women need roughly 25g of fiber per day. Men need roughly 35g per day (proportional to calorie intake).
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​What are the best sources of fiber?
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​The biggest misconception I get with clients is when they eat 3-5 servings of fruits and vegetables a day (ideally) and think that should get them to their fiber goal. Right? Wrong. Fruits and vegetables vary greatly in their fiber content and the quantity you need to consume for that amount. The top contenders in the fruit category are… drumroll please… raspberries (8g in one cup) and apples (5.5g in one medium apple). Vegetables you’d need a cup of green peas (9g) or a cup of broccoli (5g). Whole wheat spaghetti and barley win the grains category (6g per cup). And saving the best for last… our legumes (and nuts/seeds)! Beans get you almost 15g per cup, and chia seeds 10g per ounce.
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​Why are there two types of fiber!?
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​That’s right, folks, the age-old question (or maybe one you’ve literally never asked yourself before), what’s the difference between soluble versus insoluble fiber? Soluble fiber dissolves in water and forms a “gel” which slows digestion, traps cholesterol, and feeds gut bacteria (i.e., in oats, barley, psyllium, apples, citrus, beans, flaxseed). Insoluble fiber doesn’t dissolve and adds “bulk” to stool, speeding transit time and helping with bowel regularity (i.e., in wheat bran, whole grains, nuts, seeds, green beans, potato skin, cauliflower). Soluble fiber we track at approximately 2 calories per gram, and insoluble fiber is about 0.
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​To poop or not to poop, that is the question.
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​Soluble (holds water in the stool, keeping it soft) and insoluble fiber (adds bulk and helps the gut move along) together help produce well-formed stools that pass with minimal straining. However, without enough water intake, fiber can dry out and make stool too compact, making it harder to pass. Rule of thumb: increase fiber gradually, drink at least 8 cups of water daily, and for people with motility issues (IBS, hypothyroid, etc), soluble fiber is generally safer than insoluble.
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​Cancer prevention, hallelujah.
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​High fiber is linked to a reduction in colorectal cancer risk. Fiber bulks stool and promotes motility, decreasing the time carcinogens are sitting in the colon. Gut bacteria fermentation promotes healthy cell turnover and suppresses cancer cell growth. Fiber also reduces insulin and growth factor levels, which can promote tumor growth.
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​Fiber finally got its time in the spotlight, time to take a bow(el).
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​Well, if that isn’t the most fun you’ve ever had reading about a macronutrient, I don’t know what will be. If you have any tips on how you enjoy your fiber, let me know!
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If you found some value in this, please share it with a friend you think would enjoy it! And let me know if you’d like to be added to get TGIM.
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This week, my podcast recommendation is from Science Vs., “Caffeine: How Much Is Too Much.”
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With that, make it a great week!
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Until next time,
Shannon