Using sugar to the point of overeating, being overweight or sick is Gluttony, plain and simple. It is a moral weakness; it is clearly equal to being a drunk in the Bible; and Gluttony is absolutely a sin.
The Bible is crystal clear on this with no room to wiggle. Christians often don't like to hear it, but they are wrong to ignore it. It is no better than being a drunk or being an addict.
Proverbs 23:20-21 “Do not join those who drink too much wine or gorge themselves on meat, for drunkards and gluttons become poor, and drowsiness clothes them in rags.”
Proverbs 28:7 “He who keeps the law is a discerning son, but a companion of gluttons disgraces his father.”
Proverbs 23:2 “Put a knife to your throat if you are given to gluttony.”
There are even verses specifically about eating too many sweet things:
Proverbs 25:16 "If you have found honey, eat only enough for you, lest you have your fill of it and vomit it."
Abusing anything one might put into one's body is a sin, period. To say otherwise is to deny the Word.
On the other hand recreational pot use is meant only to change someone's brain chemistry and make them high or "euphoric".
Sugar and pot are not equals.
Goodnight