Regarding the formal diet, you need to be on the exclusion diet for 8 weeks before attempting to reintroduce foods. This takes about one year to do properly. You will still experience unexplained flare ups. I would not suggest attempting the fodmap diet in the UK without speaking to a nutritionist first. You will need a go referral.
The AMT is the excess of the tentative minimum tax over the regular tax. Thus, the AMT is owed only if the tentative minimum tax is greater than the regular tax. The tentative minimum tax is figured separately from the regular tax. In general, compute the tentative minimum tax by:
VAT is a consumption tax because the ultimate burden of the tax is borne by the final end consumer. It is also a type of indirect tax as the tax bearer is the consumer while the taxpayer is the seller of goods. There are three variants of VAT: Gross Product Variant, Income Variant, and Consumption Variant.