Yes, it can be done, and it is by far my favorite part of my job. I love nothing more than helping someone with IBS, SIBO, or other food intolerances eat a wider variety of foods again!
The longer I'm in practice, the more I see myself as a "restricted eating specialist"... Although, not in the same way as my functional medicine colleagues. Where the majority of folks in my profession teach and encourage people to cut out foods and restrict their eating more and more, I am often the cheerleader that helps them eat more, not less. Let's look at three of my favorite examples:
The key to reintroducing FODMAPs is to 1. treat the reason(s) you are FODMAP intolerant to begin with (i.e. kill/treat the SIBO, work on motility, de-inflame the gut, re-balance the colon microbiome) and 2. reintroduce each food systematically and carefully. Once we have at least some of our ducks in a row most people find that reintroducing FODMAPs is quite easy!
The Autoimmune Protocol (AIP) Diet is popular among people with various autoimmune diseases such as rheumatoid arthritis, Hashimoto's disease, Grave's disease, lupus/SLE, and autoimmune gastritis. Some practitioners prescribe this diet for all of their patients, no matter their health issues! And while, yes, AIP is a powerful tool, it's not the end-all-be-all healing diet, and it is quite restrictive.
The goal with AIP should be to eliminate foods, reintroduce them slowly and systematically, and ultimately cut out only your true trigger foods. What happens often, however, is that people feel better on AIP and either 1. don't want to poke the bear and test the foods again, leading to a forever-restricted diet :( or 2. they feel like crud when they reintroduce any foods. Bummer!
What needs to happen in this scenario is 1. treat your "root cause(s)" and triggers of autoimmunity (dysbiosis being huge) 2. use herbs, supplements, and occasionally medications to help the immune system function optimally and decrease inflammation and 3. use herbs, supplements, and probiotics to "promote immune tolerance" (sending "hey chill out" messages to your immune system so it doesn't want to attack everything in sight anymore).
The Low Histamine Diet is typically used when the allergic side of the immune system is acting bonkers: think, hives (uticaria), oral allergy symptoms, mast cell activation syndrome/disorder (MCAS/MCAD), eczema, asthma, and migraines. The idea is that if your immune system is churning out too much histamine, then you don't want to over-burden your body with additional histamine from food. Sadly, like the others, it is all too common for people to get "stuck" on this diet.
In order to gain some tolerance for histamine again you need to 1. address any and all dysbiosis (imbalance of bacteria, yeast, and other creepy crawlies), especially any bacteria that are known to produce histamine, 2. heal your gut to ensure you can make DAO, the enzyme that degrades histamine from food and 3. use supplements and herbs to calm down the allergic side of the immune system.
I hope this article helps you on your healing journey,