Read the following context and choose the best option to answer the question.
Context: Then I started wondering how low calorie they could be . I found a recipe for 40 calories , so of course ... I had to try it . Unfortunately ( or rather fortunately , I suppose ) , my brother has basically NO ingredients for ANYthing . So I had to substitute nearly everything in the recipe because there were no eggs / vegetable oil / applesauce , butter / margarine , salt , or baking soda / self - rising flour .
Question: Why is the speaker interested in find low calorie recipes ?
Options: 
A. They are doing a science project to determine if calories and taste are entirely related
B. They are on the marketing board of a food manufacturer and are trying to create low calorie treats
C. They are trying to determine the exact amount of calories in every ingredient for research
D. They are interested in losing weight and are trying to go about it in a systematic fashion


D