Table 2.

Body fat index (BFI) system for assessing overweight and obese cats

	BFI 30: 26–35% body fat	BFI 40: 36–45% body fat	BFI 50: 46–55% body fat	BFI 60: 56–65% body fat	BFI 70: >65% body fat
Face	Slight fat cover; defined bony structures on palpation	Slight to moderate fat cover; defined to slight bony structures on palpation	Moderate fat cover; slight to minimal bony structures on palpation	Thick fat cover; minimal to no palpable bony structures	Very thick fat cover; no palpable bony structures
Head and neck	Clear distinction between head and shoulder; loose scruff; slight scruff fat	Clear to slight distinction between head and shoulder; loose to snug scruff; slight to moderate scruff fat	Minimal distinction between head and shoulder; loose to snug scruff; slight to moderate scruff fat	Poor to no distinction between head and shoulder; snug to tight scruff; moderate to very thick scruff fat	No distinction between head and shoulder; tight scruff; very thick scruff fat
Sternum	Defined, slightly prominent; easy to palpate; slight to moderate pectoral fat	Minimally prominent; palpable; moderate pectoral fat	Poorly defined to not prominent; difficult to palpate; moderate to thick pectoral fat	Not prominent; very/extremely difficult to palpate; very/extremely thick pectoral fat	Not prominent; impossible to palpate; extremely thick pectoral fat
Scapula	Defined, slightly prominent; easy/very easy to palpate	Slightly prominent; easy to palpate	Minimally to not prominent; palpable	Not prominent; difficult to palpate	Not prominent; impossible to palpate
Ribs	Not prominent; easy to palpate	Not prominent; palpable	Not prominent; difficult to palpate	Not prominent; extremely difficult to impossible to palpate	Not prominent; impossible to palpate
Abdomen	Loose abdominal skin with minimal fat; easy to palpate abdominal contents	Obvious skin fold with moderate fat; easy to palpate abdominal contents	Heavy fat pad; difficult to palpate abdominal contents	Very heavy fat pad; indistinct from abdominal fat; impossible to palpate abdominal contents	Extremely heavy fat pad; indistinct from abdominal fat; impossible to palpate abdominal contents
Tail base	Slightly to minimally prominent bony structure; palpable; slight fat cover	Slightly to minimally prominent bony structure; palpable; slight to moderate fat cover	Poorly defined bony structure; difficult to palpate; moderate to thick fat cover	Bony structure very/extremely difficult to palpate; very thick to extremely thick fat cover	Bony structure very/extremely difficult to palpate; extremely thick fat cover
Shape from behind	Clear to poor muscle definition under a thin to moderate layer of fat	Poor muscle definition under a moderate layer of fat	Rounded appearance; thick layer of fat	Rounded to square appearance; thick layer of fat	Square appearance; very thick layer of fat
Shape from the side	No abdominal tuck	Slight abdominal bulge	Moderate abdominal	Severe abdominal bulge	Very severe abdominal bulge
Shape from above	Slight hourglass/straightening of waist with no hourglass indentation	Straightening of waist with no hourglass indentation and/or mild distension of the abdomen	Broadened back	Severely broadened back	Extremely broadened back

BFI system validated as a method to estimate body composition in overweight and obese cats ¹⁴