Clue: Struggling after heavy meal? Nice? No! Turn to dietary wisdom from … (5,3,4,4,3,3,4)
Answer: NEVER EAT MORE THAN YOU CAN LIFT
Explanation: Definition: dietary wisdom
(AFTER HEAVY MEAL NICE NO TURN TO)*. I have my usual reservations about this kind of clue, but for once the long anagram fodder was actually useful to me in solving it: with a few crossing letters I guessed the first six words, then used the anagram to get LIFT (after which I convinced myself that "I knew that"). This wise saying comes from MISS PIGGY, hence the link to the next clue