That’s not quite Newton’s 3rd Law of Motion, but it may as well be my custom law of weight loss. In three days, from Tuesday through Friday, my weight decreased 3.3 pounds. In three days, from Friday through today (Monday), my weight increased 4.2 pounds. What’s that all about?
Let me start with the good news. Even though I ate out a decent amount, I made good choices. I had chicken and veggie thin crust pizza with non-dairy cheese (this is a meal I was able to calculate accurately, and I was very impressed with the results). I did not have movie theatre popcorn, but rather enjoyed my SmartFood popcorn at the theatre (yes, I’m one of those people who likes to carry a big purse). I had grilled chicken and veggies at the Chinese restaurant. I chose Greek food over something more fattening for going out to lunch yesterday. Some definite wins in the selection area!
My decisions were not all perfect. I ate a dark chocolate KitKat; I had a Torchy’s taco of the month (this is the item I likely significantly overestimated, as the closest taco to the one I ate that had nutritional information available also had cheese and very caloric refried black beans that mine did not); I gave into my ice cream cravings (but, I did have a non-dairy base, so that saved calories, as well as abdominal discomfort). I also had two small glasses of wine, but again, that I could have chosen much worse.
It wasn’t all bad… but, probably not the right decision for the weekend before my final weigh in. My daily weight change from my bathroom scale was +1.8lbs, +0.4lbs, +1.6lbs (actually a little less than what my work scale showed in total).
I decided to log my food intake for Friday, Saturday, and Sunday and was as accurate as I could be, even overestimating items that I don’t have reliable data on. So, for a worse case scenario, I consumed no more than 5050 calories total for three days.
I looked at a few Basal Metabolic Rate calculators and the lowest estimate was 1264 calories/day. Now, those are just calories for my body to function at rest, not including any energy expenditures, but I’ll keep it there to be “safe”.
1264 calories * 3 = 3792 calories. I consumed 5050 calories, so my calorie excess was 1258 calories, assuming I expended no additional energy, which is an incorrect assumption. Considering calories alone, my weight should have increased no more than 0.36lbs over the weekend, not 4.2lbs.
I’ve never been a believer in the simplicity of 3500 calories being equal to 1 pound. I’m sure that’s part of the equation, but there’s a lot more going on. Researchers over the past few years seem to agree with this notion. This is a blog article from a registered dietician that provides great references and links. Both the NIH and the Pennington Biomedical Research Center (a former customer of mine when I worked for the scientific instrument company) sites have interesting diet calculators that show that actual weight loss predictions differ from the 3500-calorie/pound model.
In fact, I did a simulation using the Pennington Excel sheet looking at a slow weight loss over the course of a year, assuming an approximate calorie intake of 1500 calories/day. Take a look at that here: IJO.
You’ll notice that the dynamic model (the red line) predicts a lot slower weight loss than the 3500 rule prediction (the blue line). This is because, among other factors, metabolism plays a role and as your weight decreases, your body needs less calories to sustain itself.
The models that both studies use for predicting weight loss are different, but the outcome is similar. An publically available 2011 journal article is available from the NIH site: Quantification of the effect of energy imbalance on bodyweight. This is a good summary of their model based upon experimental weight change data.
I am happy to see this research is it is based upon actual weight change research! I would love to get into a weight change study, as it has always been fascinating to me.
The above studies are looking at long-term weight change, but what about fluctuations in the short term? One pint of water is 1.04 pounds, so one obvious source of fluctuation is fluctuations in hydration. What affects that? Salt content, hormones, muscle composition, carbohydrate intake, etc. etc.
Women retain water during their cycle. When we are nearing our periods, our hormone levels are high and that affects the way gas and stool move through the digestive tract. Speaking of stool (everyone’s favorite topic, I know), the more waste that builds up, the more bloated you may feel and the higher your weight will be.
Carbohydrates cause increased weight because they are converted to glycogen in the muscles and liver and are stored with some extra water. In fact, according to the American Council on Exercise, each gram of glycogen stores 2.7 grams of water with it! This isn’t the same as water retention, but it definitely affects your immediate weight. This can be even more problematic if you’re reducing carbohydrates while eating healthy because your body hordes them to store them for later use!
Excess sodium (read processed foods) causes you to gain weight because you retain water. You fix this by increasing your water intake which may sound counterintuitive because you’re drinking more water, but that helps dilute the sodium and flush it out.
Basically, what you eat and drink affects your weight in the short term. The best thing to do is be consistent on what you eat (not my strong point) and avoid processed foods. Eating out is always a wild card, so even if your choices are decent, it’s probably best to avoid this the weekend before ending your Diet Bet.
I’ll let you know that the scale says on Wednesday!! I like to keep things interesting, apparently….