I did not feel colder myself... When I am feeling cold, it is usually because 1) I am tired, 2) I am sick, 3) I am hungry and very weak, 4) I have my periods.
However, it may be due to the diet. I am sure a CDC will be able to answer better than me! Or maybe you could ask your CDC the next time to see her/him?
Did you know that when you shiver it is your bodies natural response to generate heat in the muscles to create warmth in the body, and this burns a lot of calories.