Diabetes 2 Diet

Hello. I am so confused about the decision null and alternative hypothesis, I am confused as to which is which.

Thus, for example, is one that in the following example:

Is a diet without reducing sugar diabetes? 10 people are randomly selected and placed on a sugar-free diet for a month. sugar readings are taken before and after. Now, how can I check if the power of free reduced sugar diabetes??

I basically just want to know what the draw and will hypthosis Altner ....

Thank you!

Ho (null) sugar-free diet has no effect on diabetes
H1 sugar-free diet reduces diabetes