My Remicade cycle was increased in frequency from 8 to 6 weeks, which was effectively an increase in dosage. This was not due to blood labs, rather it was due to being symptomatic in the 6-8 week mark after infusion. My dosage has also been increased and decreased based on fluctuations in my weight. It went up and down when my weight went up and down. The initial dosage of all biologics - or so I thought- is based on weight.

I did have a Remicade blood test and don't have the results yet, and I will be curious as to what action it might lead to if the Remicade level is off.

Have you discussed with your doctor the perceived impact of your dietary changes? The problem with your analysis is you are making an assumption on cause and effect and it's not clear what that is based on. Absent proof, you might not be correct.

I had both my Humira and Remicade cycles increased, then decreased, then increased again, so and so forth. I haven’t been on them for almost two years now, but I do remember that my weight was a struggle. I could never go up, and stopping the medications was the only way to gain weight. My diet consisted of a low FODMAP diet, because it was simple and non irritable, although it could get boring.

It really all depends on your body.  Keep calm and all will be well. I hope that answers your question a bit.