Fatten Up solution
by Kegler

Eight answers add OZ before entry; adding eight ounces means these answers collectively GAIN HALF A POUND.

Fatten Up solution grid

Across
1DR(AFT)Y
6BOOZERS (ROBES anag)
12MOZ + ART
13AVOCAtions + DO
14HIDE (2 defs)
16fRITZ
18TEEThERS
19IRK (hidden)
20I + NCISE (SINCE anag)
22A(EO)N
24CROZIE + R (RICE anag)
25ORG (1st letters)
26GAIN HALF A POUND
29OLD (last letters)
30AMYLASE (A MEASLY anag)
33ZEAL (hidden)
36ORATOR (TO ROAR anag)
39gOWN
40BAPTIZE ("TAP BUYS" spoonerism)
42RAG + E
43A + X + ED
44K(NAVER)Y (RAVEN anag)
45DOZENS (SEND anag)
46DESSERT ("DESERT" hom)
47PRESET (PETER'S anag)
Down
2ROUE + N
3A(Z)TECS (CASTE anag)
4F + ACTION + AL
5T(R)EE
6BRISTO + L (BISTRO anag)
7OVER + T
8ZO + O + KEEPER (rev)
9ECRU (hidden)
10RAISE ("RAZE" hom)
11DOZ + ING (GIN anag)
12MA + TIN + G
15DA(I)Z
17T + HORNY
21SC + HMOOZES (HOMES anag)
22AROMATIZE (TO EZRA I'M A anag)
23GAL + E + NA (AN rev)
27FAN BELT ("BAN FELT" spoonerism)
28D(U)RESS
29OZpARKS
31LYNX ("LINKS" hom)
32STILES (2 defs)
34AL(GA)E
35A + W + ARE
37OZONE ("WON" hom)
38RE(V)S
41PO + OR