Track fiber in your macros and add it gradually
Added
Fiber is a carbohydrate, but it supplies fewer calories than other carbs, so it's worth logging separately if you track macros. Get it from a mix of beans, lentils, whole grains, fruits and vegetables (keep the peels on), and add it over a few weeks with plenty of fluids to avoid gas and bloating.
The result
Result: MedlinePlus (NIH): adults are advised to eat 21 to 38 grams of fiber a day, while Americans average about 16 grams; fiber provides about half the calories per gram of other carbohydrates.
Note: Not medical advice. Talk to your doctor before changing your training, diet, or supplements.
Source
MedlinePlus (National Library of Medicine): Fiber (opens the original source in a new tab). Check it for the latest numbers before you act.