Sunday, April 28, 2013

Food Journals and Elimination Diets


Food Journals


Keeping a food journal can help keep track of what foods irritate you and take some of the guesswork out of the diet planning process for IBD.  One of the biggest mistakes that those with Crohns and Ulcerative Colitis can make is to unnecessarily limit the diversity of their diets based on unfounded diet claims or by singular experiences under poorly isolated conditions.

It’s human nature to react negatively when your body has an adverse reaction following a meal.  Evolution developed the instinct to avoid foods that make us sick – eating berries that make you throw up may indicate they were poisonous to the system.  As such, we developed visceral reactions to food that made us ill.  Just think back to a food you absolutely won’t eat – there may be a negative association with a single incident.  For me, there are two that come to mind – Moo Goo Gai Pan (resulted in a case of food poisoning) and blue Gatorade (I used to mix it with my colonoscopy prep drinks – now it has that as a permanent association for me).  For individuals with inflammatory bowel disease, those single incidents occur a lot, and may or may not be related to what has recently been consumed.

The second factor that skews our rational thought with food reactions is proximity.  If we get sick 10 minutes after eating a particular food for dinner, we tend to blame that food and not the early afternoon snack.  Even worse, the incident may not be food related at all – it may just be an idiosyncratic response to medications the previous day, or to an environmental allergy.  Eliminating a particular food from our diet because of a single incident just doesn’t make sense.  How do we figure out what foods cause distress, then?
The first step is creating a food journal or diary.  It can be a small notepad you carry with you, an Excel spreadsheet on your computer, or an app on your smartphone (http://www.foodallergydetective.com/ is an iPhone app that was originally created for tracking allergies, but has applicability for IBD also).  The food journal needs to be updated with everything you eat (even those quick snacks).  I’d suggest tracking the following items:

·         Time/Date
·         Type of Food (use the food pyramid categories)
·         Food Description
·         Preparation (e.g. Fried, Baked, Grilled)
·         Amount

Each food item should be added as a separate entry, so a steak with mashed potatoes and asparagus should be three separate items.  Don’t forget to include drinks.

You can keep a symptom journal either with the food journal or as a separate entity that you later correlate (very easy if you have two tabs on a spreadsheet).  The symptom journal should track:

·         Date/Time
·         Category (Symptom, Medication, Bowel Movement)
·         Description

After a period of a month or two, you will have enough data to begin analyzing it.  When looking at the data, here are a few tips:

·         Calculate your average number of bowel movements a day (for a baseline). 
·         Calculate the average time after eating before your next bowel movement.
·         Pick a reasonable period (two hours is a good start) and look for any symptoms that appear within two hours of eating a particular food.
·         Identify any foods that have a stronger correlation than others (three times is a simple rule.  For those of you who are statistics-driven, try anything more than 2 standard deviations from average).
·         There will likely be a dose-response curve for foods you can’t tolerate.  As an example, those who are lactose intolerant can generally consume small amounts, with symptoms appearing and worsening as the amounts increase.
·         Eliminate the problem foods and see if the overall numbers change.

There are a few variants on a journal that are more rigid – namely the exclusion diet and the elimination diet.  With an exclusion diet, you remove a particular food from your diet for a period of time (generally several weeks) to see if symptoms improve.  With an isolation diet, you start with a small number of foods that you know do not cause symptoms (e.g. Ensure) and then slowly add items one at a time to determine if they have a symptom impact.  As with the journal, it may take multiple iterations of removal/addition to be sure that a particular food isn’t impacting your symptoms.

There are some downsides to elimination diets.  First, they are notoriously difficult to isolate specific problems – for example you may think that you have an intolerance to chicken and eliminate if from your diet, when in reality it is the peanut oil the chicken is cooked in.  Second, tolerances may change based on your current condition, requiring the diet be revisited periodically.  Third, individuals may have a tendency to remove too much from an already limited diet.  Finally, even though there may be some symptom changes due to food, there is no evidence of food impacting actual disease progression.(1)

Bottom Line


·         Food journals can provide insight into what food trigger symptoms.
·         Elimination and isolation diets can help fast-track food journal results, with some potential pitfalls.
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1.       Pearson, M., K. Teahon, A. Jonathan Levi, and I. Bjarnason. "Food intolerance and Crohn's disease." Gut 34, no. 6 (1993): 783-787.

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