"D'autant que" and Subjunctive

Question

In one of the dictées, I ran into the expression "d'autant que je me souvienne"...par exemple, je n'aime pas les aliments sucrés d'autant que je me souvienne." I haven't liked sweet foods for as long as I can remember (or maybe more literally "for as much as I remember."  Why is "de" used before avant que?  Does that kind of replace "for" in English?  And why does it take the subjunctive?  I'm guessing that perhaps it takes the subjunctive because memory is fallible and perhaps there's an element of doubt?  Perhaps one is not remembering correctly?

Cécile Janty-Davies · Accepted Answer

If I have understood your question correctly Rhonda, these two French expressions are quite different despite their similar appearance:
Autant que = "as much as" or "as far as"
This is used for comparisons or to express extent:
Je t'aime autant que lui = I love you as much as him
Autant que je sache = As far as I know 
Mange autant que tu veux = Eat as much as you want

D'autant que = "especially since" or "all the more so because"
This introduces a reason or justification, adding emphasis to an explanation:
Je suis fatigué, d'autant que j'ai mal dormi = I'm tired, especially since I slept poorly
C'est difficile, d'autant que nous manquons de temps = It's difficult, especially since we're short on time
You are correct about the use of the subjunctive in the verb 'se souvenir' and you will notice that 'sache' the subjunctive of 'savoir' in an earlier example is for the same reason.
Hope this helps!

Maarten Kamp · Answer

Cécile,

I think the following is the English phrase and one of the “ correct answers “ for French translation that Rhonda is referring to :

“ I've had a sweet tooth for as long as I can remember “

“J'ai un faible pour les sucreries d'autant que je me souvienne”

https://progress.lawlessfrench.com/my-languages/french/exercises/overview/2391

It is the only one of the options listed as correct that didn’t use ‘depuis’.

Wordreference gives one translation of “ d’autant que “ into English as ‘ as far as ‘.

https://www.wordreference.com/fren/d%27autant%20que

Larousse on the other hand states that ‘ d’autant (plus) que would take the infinitive and doesn’t seem to me to specifically note the use seen in this exercise.

https://www.larousse.fr/dictionnaires/francais/autant/6551#locution

Robert states the following “ D'autant que locution conjonctive : vu, attendu que. Je n'y suis pas allé, d'autant qu'il était déjà tard “

https://dictionnaire.lerobert.com/definition/autant

Can you clarify further given the differences ?