Answer
$\Delta m=6.46\ kg$
Work Step by Step
The extra energy consumption by Candy is given by:
Energy content of butter: 35 Cal/teaspoon
Yearly consumption: 4 teaspoons/day=1460 teaspoons/year.
Therefore $\Delta E=213.95\ MJ$
The energy content of fat is 33.1 MJ/kg, hence the fat increase would be:
$\Delta m=6.46\ kg$
