Please help me determine the cause of my recent weight gain.
A bit of history is probably important to answer the question. Since March, I have lost 59 lbs by calorie restriction, a healthy diet, and cardiovascular exercise. I have not trained with weights other than carrying 2 lb hand weights and a 8 lb to 20 lb weight vest while walking. Furthermore, I have not used any weights during the time period in question. Last Sunday, I weighed in at 176.5 lbs, my lowest weight since high school. On Thursday, I weighed in at 182 lbs. Last night, I weighed in at 189 lbs. At each of these weigh ins, my percentage body fat was approximately 14% (+/- .5%).
My weight can easily swing five pounds in a 24 hour period of time depending on calories consumed, hydration levels, regularity of bowel movements, and the timing of my weigh ins. That said, these factors remained relatively constant throughout the week and do not, alone, account for the twelve pound swing in my weight.
Caloric Intake and Expenditure
My caloric intake for the week was approximately 15k calories. My caloric expenditure for the week, on top of my RMR
, was 9k calories, as determined by a Polar F11 HRM
worn during all exercise. This would, presumably, lead to weight loss. However, 2k of the additional caloric expenditure came on Thursday and another 3k of the additional caloric expenditure came on Saturday. Both days resulted in significant calorie deficits.
Theory, Being What It Is
It is my understanding that when the body is stressed through exercise and calorie deprivation at these levels that the body stores extra energy in some form, which can account for temporary weight gain when one might expect weight loss. This has happened several times to me and the weight melts off after a few days without any substantial change in my diet or exercise. However, such a change in my weight has never been so large before. Is this a plausible answer to my question? What is this mechanism called? Are there other factors I am not considering?