When I work with patients one on one, the one nutrient that is almost significantly lower than the recommended amount is fiber. Whether you want to reduce chronic disease, decrease inflammation, or lose weight the solution is the same- increase fiber in your diet. I recommend gradually (too fast can increase gas/bloating) increasing fiber in the diet until you are getting at least 40 grams a day. The best sources of fiber in the diet are: beans and lentils, vegetables, fruits (whole not juice), whole grains, and nuts and seeds.
Fiber is also a “prebiotic” which means it supports the growth and health of our gut bacteria or “microbiota”. Fiber helps improve the gut microbiome diversity and supports the growth of healthy bacteria. The health of our microbiome directly impacts our own health.
Use an online app like, My Fitness Pal, to track your daily fiber intake. Increasing fiber in the diet can: lower cholesterol, keep you full and help you lose weight, stabilize your blood sugar and reduce the risk of diabetes, and decrease the risk of colon cancer. One way to dramatically increase your fiber is to swap one serving of animal protein with plant protein (beans/lentils) each day. Another strategy is to add a vegetable or fruit to each meal.
If you want to learn more, check out one of my favorite books, “Fiber Fueled” by Dr Will Bulsiewicz. See some of the scientific studies about fiber that into his book here: https://theplantfedgut.com/research/.