I doubt a hamster can eat itself to death but it can lead to obesity and that can trigger further health problems.
What I'd recommend doing is gradually reducing the amount you feed and picking a few bits out of the hoard every day - keep doing this until you reach a consistent amount
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Minion to Daisy, Lily, Harry and Peanut <3
Gone but never forgotten
Willow - 18:27 18th November 2016