What are Melfi's sugar substitutes?

In Episode 2x05 Big Girls Don't Cry of The Sopranos, Dr. Melfi has the following dialogue with her therapist and former teacher, Dr. Kupferberg:

Kupferberg: You mentioned you've put on a little weight lately. Do you think the overeating has anything to do with your patient?

[Melfi shrugs reluctantly]

Kupferberg: What is it you're not telling me, Jennifer?

Melfi: I don't know. I don't know what you mean.

Kupferberg: [Unconvinced] Okay.

Melfi: I don't. What are you driving at?

Kupferberg: Just, watch your intake of sugar. And sugar substitutes.

Both characters seem to be quite uncomfortable throughout the dialogue.

What is Kupferberg hinting at with the sugar substitutes?

If possible, try to answer without spoiling too much from later episodes.

Best Answer

Melfi has a history of alcohol abuse.

Kupferberg is aware of this and is afraid that Melfi might use alcohol to escape her guilt about abandoning Toni. He uses the term sugar substitutes as a euphemism for alcohol.

Alcohol is not a sugar in the chemical sense, but rather a product of fermenting sugar. It can however, toxic effects left aside, serve as a nutrient for humans, similar to sugar and other carbohydrates. In particular, excessive alcohol consumption often results in weight gain.

Kupferberg knows that if he accused Melfi straight away she would shut him out again (as she did in a previous session on the same episode). He instead tries a more subtle approach, hoping that Melfi will understand his warning.

Later in that same episode, when Melfi calls Tony to tell him that she is willing to treat him again, she is repeatedly drinking from a glass of red wine. This further indicates that she uses alcohol as a means of dealing with a stressful situation.