By now you've probably heard about the benefits of fiber in your diet, such as improving digestion, decreasing risk factors for heart disease, and helping with blood sugar levels.
So if some fiber is good, then more must be better, right? Not necessarily, and here's why.
We live in a world of extremes. Our thinking tends to be all-or-nothing, which in the world of psychology is known as a "thinking error" because nothing is that simple. We assume that if something is bad for us then we should avoid it completely (remember the low-fat craze which totally backfired?). And on the flip side, we assume that if something is good then the more the better.
However, extremes of anything cause problems. If I ate baby carrots all day long I'd turn orange because my body couldn't handle the excessive dose of vitamin A. I'd also be deficient in carbohydrates, proteins and fats – the 3 essential macronutrients. And if all I ate was chocolate chip cookies I'd be deficient in protein (at leats the cookie has substantial amounts of carbs and fats). My point is that when taken to extremes any food can cause harm.
Same thing with fiber. If a person doesn't consume enough fiber they are more likely to be constipated because the fiber (insoluble version) holds on to water and facilitates formation of bulky soft stools. But at the other extreme excessive fiber can cause also cause constipation because there is too much bulk to the stools and food moves too slowly through the GI tract.
I've seen this become a problem in recent years as the food industry has hyper-fortified products with fiber. There's an abundance of foods now containing more than an entire day's worth of fiber into one serving, and think about what happens if you eat multiple servings of these foods.
As I always say, everything needs balance. Not too much nor too little and your body will be just fine. How much is enough, the current guidelines say 38 grams of fiber per day for men, and 25 for women. Your needs may change with age, medical conditions or other circumstances.