You're suffering some sort of symptoms and you're pretty sure it's a digestive problem but not sure where to start or what to blame... Know the feeling!
Well good news, there's the simple way, and the hard way to sorting you out.
You can get a food intolerance or food sensitivity blood test done. These will take a small blood sample and test you against 60 - 200+ foods, colours, preservatives etc (the more you pay, the more they'll test!
There is some negative press about such tests, but in my personal experience and those of clients it's been very accurate and a real time saver. The usual advice of go somewhere reputable certainly applies!
The other way is to try an elimination diet. The idea being being you eliminate suspect foods, those that you think may be the cause and have a look at the most common causes which seems to be the logical place to start.
Steps to take by going solo:
1. Keep a food dairy
2. Make a note of any discomfort or symptoms you feel from bloating to lethargy
2. Identify all possible culprits
3. Eliminate all culprits until you suffer no more symptoms
4. Go TWO full weeks without any suspect foods
5. One at a time, slowly reintroduce each of the suspects and check for a reaction. Reintroduce no more than one every couple of days for accuracy.
6. If you suffer no reaction, you may reintroduce that food into your diet. If not, eliminate the food intolerance for a couple of months before trying to reintroduce again. The hope is you can restore your gut to a point where you can hopefully consume a wider selection of the culprits once your digestive health improves.
7. If you are reacting to multiple food sensitivites or intolerances, I'd strongly suggest seeking a Dietitian for ongoing help, this can be a long process and good guidance and adherence is paramount.
Some reactions may even run in to the next, meaning you may be intolerant to two foods but only blaming one... As mentioned, it can get tricky but not impossible!
It's really as simple as you make this process, just remember:
What gets measured, gets managed
You must quantify what your eating so patterns occur and assumptions made. Start by eliminating the common culprits and keep notes of anything suspect, and of course seek further medical advice if needed.