Campuses:

Mathematically Modeling the Influence of Eating Rates on Weight Gain and Obesity

Friday, March 27, 2015 - 2:30pm - 2:55pm
Keller 3-180
Diana Thomas (Montclair State University)
Background:
Eating rate studies have long established that obese subjects eat faster than the lean. Moreover, data indicated that restrained eaters (defined as eaters who intentionally restrict food intake to control body weight) exhibit linear cumulative eating curves and unrestrained follow a non-linear quadratic curve. Past studies were limited because investigators needed to directly measure bite rates using laboratory devices.


Methods:
A newly designed portable sensor detecting bite rates was applied to determine whether BMI predicted eating rates in free-living subjects. Regression and quartile analysis were applied to determine that the obese do not eat faster than the lean, but rather eat longer. Thus, it was hypothesized that all individuals cumulatively accrue food during a meal as a saturation function rather than separate linear versus quadratic curves. The logistic differential equation was used to model cumulative eating curves (food ingested in grams as a function of time). From cumulative eating rate data, parameters $r$ and $K$ were estimated for the logistic differential equation model for four different groups of eaters; unrestrained and restrained eaters directed to eat as much as they can, and unrestrained and restrained eaters directed to eat as much as they feel comfortable with.

Results:
BMI did not predict eating bite rate. Bite rates were fairly constant with highest bite rates observed in normal weight subjects. The quartile analysis revealed that eating duration was positively associated to BMI. The parameter values derived for the logistic differential equation model were $r=0.04,K=1500$ (unrestrained eat as much as you can), $r=0.14, K=450$ (unrestrained eat as much as you feel comfortable with), $r=0.05, K=1100$, (restrained eat as much as you can), and $r=0.06, K=800$ (restrained eat as much as you feel comfortable with).

Conclusions:
Obesity is not related to eating bite rates. Meal duration is a predictor of total consumed energy intake and is associated with higher BMI. Unrestrained eaters directed to eat as much as they feel comfortable with exhibit different eating behavior in comparison to restrained eaters.