n=1 Personal Informatics
diet and weight loss | food tracking
Shaun Wallace is a part-time graduate student at Brown University and was tasked to do a quantified-self project. He discusses his experiment to test the relationship between the food he consumes and his weight change and productivity. The presentation took place at the Boston Quantified Self meetup on April 21, 2015.
Journal | scale
My name is Shaun Wallace, I work at Brown University and I'm also a part-time graduate student and that partially explains where this experiment came from. We were charged with coming up with a personal informatics experiment and I was highly motivated because I'm getting married on May 29 and I have the pressure of trying to lose weight for the wedding which is not a fun experience. So why don't I kill two birds with one stone and make a study around that struggle.
So basically what I'm trying to figure out what food and drinks am I sensitive to, and if I'm sensitive to any of these food or drinks does that affect my overall well-being or productivity in any way.
So how I started off is I started with low reactivity foods. I would introduce one new food each day, and if I gained weight or experiences symptoms, say a headache, bloating, diarrhea, all of those things none of us want to experience. That could indicate a sensitivity or reactivity.
So most people talk about this, they’ll probably follow some type of this situation, and yes, it is painful to go through this.
So my goal is to conduct an n=1 experiment. The study revolves around my health, my well-being, weight loss. In terms of finding my conclusion it relies heavily on correlation statistics and you know that comprises tons of data points.
In terms of how I ran it, it was over 28 days, February 27 to March 27. Some basic rules; I only ate until I was full. I didn’t exercise at all except for walking to class or to a grocery store.
Water intake was extremely important because I didn’t want my weight change to be due to water. So I would weigh in the morning, alcohol drinks, minutes of activity, all those would add up to find out you know, that it was equal and I was fine and I wasn’t actually losing the weight because of water changes.
This is my first hypothesis which is sensitivity, reactivity to foods can cause certain weight changes. Also, hypothesis two revolves around the exact same relationship but in terms of my mood, stress, energy, and how my body feels. And all four of those are you know subjected measures that comprise my overall well-being.
My independent variable was one new food each day. I kept a comprehensive food and drink journal I wrote down everything that I had. The baseline for foods were all based upon being 5% or less reactive. That data was based on 10,000 studies from nutritionists from New York.
My dependent variable was obviously my weight change, going up and down and that was a comparison from the night before to the morning after.
My next dependent variable is my overall well-being was just my own subjective score of stress, mood, energy, and body from 0 to 9 and I tracked that three times a day.
Other variables I tracked just to make sure that they weren't the things causing my weight change. my overall well-being was productivity, work at school, what I did for the wedding, music, social life, relaxation, how many times I woke up, the amount of alcohol drinks I had, coffee, tea.
So the first phase I get to have whatever I want and that kind of informs what I have during the other phases; these are are just some basic statistics. Since these were over three days these are kind of all over the place but this is kind of what I wanted because I wanted to see what was causing these weight changes.
And the second phase was when I would introduce one new food each day, and the first day was kind of let my body recover. This is the same as phase one, I get to do whatever I want. This had a massive correlation between weight change and reactivity. A lot of that which I will get to later is due to over drinking.
The last part was where I was testing more reactive foods because I get because I got over the things that had less chance and that’s where I was really experiencing big shifts in weight due to introducing foods that didn’t agree with my body.
The overall results point to that my weight change correlated very much to reactivity, my overall well-being not so, my productivity had absolutely no relation to reactivity whatsoever.
So this is my overall change of weight throughout the study, between my max weight and minimum weight I lost 10 pounds which was awesome. But it was all over the place as soon as you got into the second half of the study that line of linear regression that fits really well, that’s when I was - I didn’t have any reactive foods for 10 days in a row and I was just gradually losing weight.
I performed a chi-square test to kind of see, hey does my weight change based on my positive and negative weight I had, and this goes again with mean weight. So it shows that even though I did lose weight on days where I was non-reactive, there’s still some days I gained weight just because your body naturally fluctuates.
So in terms of sensitivity and all the measures of well-being, nothing really correlated that much, only my body more so but that’s kind of an obvious conclusion because obviously if I’m sensitive to something I could suffer bloating or headaches or all these various different measures.
Here I went through and I would look at the means and the effect sizes so obviously, my body and reactivity had a large effect size. Nothing else really had a large effect size with it.
So a really important thing was like, hey did anything else affect my wellbeing or my weight change. the only thing that really correlated to anything else was relaxation and productivity, my productivity was a little bit down in the evenings when I relaxed but that’s obvious.
The biggest conclusion that I found was when I more than five drinks of alcohol I suffered massive weight changes, massive weight changes. If I had less than five it didn’t matter. And I actually tested alcohol one day just by itself. I tested wine one day, I tested beer. I was perfectly fine. I was losing weight during drinking two glasses of wine and having chocolate every day.
So, you can see here there's just an absolute massive gap. Not a huge difference in wellbeing here, so you're wondering what foods was I bad with.
Shrimp, which had an 85% chance, tomato sauce had an 85% chance. Parsnips had less than five. I don't know how that happened but I had bad bloating with that that was terrible. Cheeses that was bad too, and the effect of the four reactive foods that I had they still related to my weight change but not as much as the alcohol intake. So my rate of weight change was only negative, 0.1 pounds per day. Whereas otherwise I didn’t have them and was losing 0.74 pounds a day.
So if you have any question I’d be happy to answer them.