I'm confused on it myself, but here's the loose version. When your body/mind has demons, those demons love garlic, onion, shallots, tobacco, alcohol, drugs. When you take a large quantity of garlic, like 1 clove a day or more, it pleases these demons and you don't go "down" emotionally.

Normally you would not crave onion or garlic if these demons, which influence your mind and body, were not present. There is a sensation of big uncontrolable motivation/passion (rajas) when you have tamas (demons or darkness) in you. But it's meaningless passion that leads to nothing. For example, the slaves during the Egyptian times were fed garlic, and when the garlic was restricted, they rebelled because they had no strength of the body. The (Vikings?) called it the evil juice.

Scientifically, when you stop eating it, except small amounts, the body starts detoxing it and your armpits smells. And dark emotions, including anger and lust, become uncontrollable. In raw form garlic causes anger, in cooked form, perverse lust, hence why it's an aphrodisiac.

=====
file from Nov 2019
recovered Jan 2021

no idea about context.