# How would I analyze this sugar-elimination Quantified Self experiment?

I'm testing whether sugar consumption is making my stomach upset, with an unknown lag.

My basic plan is:

• Get 7 sugarfree and 7 regular, or 'sugarfull' Grape Powerades
• Label 14 paper bags with consecutive dates, and have someone else secretly put them into the bags in consecutive pairs
• So day 1 and day 2 will be the same kind of drink, then day 3 and day 4 might be the same
• Drink each on its date, and record how I feel throughout each day
• Join the data to have the following columns: date, sugarfull_1day_ago (binary), sugarfull_2day_ago (binary), sugarfull_1day_ago*sugarfull_2day_ago (binary), outcome (avg of ~5 0-5 ratings)

Then I'd do a standard linear regression. Here are the potential issues that I see:

• Outcome is subjective, and a '2' doesn't necessarily mean 2x a '1' (ordinal variable)
• I'm not sure that I'm accounting for 'spillover effects' properly, particularly if the effect lasts 3 days, or is cumulative
• 14 samples is not very many

What do people think, are there any tweaks that could make this experimental plan more rigorous? I have not started yet, so I'm open to any suggestions.