Body Fat Index – What Does That Mean?

We have all heard of BMI (body mass index)  – even if we weren’t sure what it stood for – we know it has to do with our body weight.  It indicates what is considered to be a healthy weight based on your height and age.  In animals we use the term BFI (body fat index) to determine how over (or under) weight a pet is.  The calculations are based on weight and specific measurements across the body to determine ideal body size.

We often don’t think of our pet being overweight when we are told they need to drop about 5 lbs.  We think – 5 lbs?, that’s it? – that isn’t very much at all.  Well it is true that 5 lbs isn’t much… on a adult human body that weighs over 120 lbs.  However 5 lbs on a dog that weighs only 30 lbs is about 20% of their total body mass.  Think of that on the average adult human.  Let’s say the adult is 145 lbs, 20% is 29 lbs!  Now that seems like a fair bit, doesn’t it?

To give an even better perspective let’s take a look at our Biggest Loser Contestants.  In this chart it shows each contestants weight, ideal weight, what that equates to in terms of BFI and how much weight they need to lose to reach an ideal weight.  Ideal weight is considered to be a BFI in the 20% range (from 16-25%) in both cats and dogs.

ContestantStarting WeightIdeal WeightCurrent BFILbs to Lose
Jojo4.3 kg / 9.5 lbs2.4 kg / 5.3 lbs55.0%4.2
Poko9.6 kg / 21.1 lbs5.4 kg / 11.9 lbs54.6%9.2
Piper8.5 kg / 18.7 lbs4.4 kg / 9.9 lbs57.8%8.8
Gunner20.2 kg / 44.4 lbs11.4 kg/ 25 lbs54.6%19.4
Lucky9.1 kg /20 lbs5.7 kg / 12.5 lbs47.4%7.5
Playdoh5.7 kg / 12.5 lbs4.6 kg / 10.1 lbs35.0%2.4
Aspen38.6 kg / 85 lbs23.6 kg / 52 lbs50.9%33

Now let’s look at these BFI’s on a human adult.  This chart shows how much an average adult male would weigh if he were the same BFI percentage as the animals above and how much he would need to lose to get back to the healthy weight.

Healthy Adult MaleOverWeight Lbs to Lose
83.5 kg / 183.7 lbsif 55% BFI then –>148.6 kg / 327 lbs143.3
83.5 kg / 183.7 lbs if 54.6% BFI then –>147.2 kg / 323.8 lbs140.1
83.5 kg / 183.7 lbs if 57.8% BFI then –>158.4 kg / 348.5 lbs164.8
83.5 kg / 183.7 lbs if 54.6% BFI then –>147.2 kg / 323.8 lbs140.1
83.5 kg / 183.7 lbsif 47.4% BFI then –>127 kg / 279.4 lbs95.7
83.5 kg / 183.7 lbsif 35% BFI then –>102.7 kg / 226 lbs42.3
83.5 kg / 183.7 lbs if 50.9% BFI then –>136.8 kg / 299.6 lbs115.9

Let’s look at a couple cross comparisons:  Jojo is at a BFI of 55% and ideally should weigh 5.3 lbs, she needs to lose 4.2 lbs to get to her ideal weight.  The same BFI in an adult male who should ideally weigh 184 lbs, would need to lose 143 lbs to achieve that goal.  The 2.4 lbs that Playdoh needs to lose is equal to this adult male needing to lose 42.3 lbs –  and in both cases that puts this male at a BFI of 20%, which in humans is actually still quite high.  Really this male would need to lose even more weight to reach what is considered a healthy BMI comparable to the equivalent healthy BFI in your pet.

Now let’s look at some food comparisons (provided by Hill’s Pet Nutrition):  whole bar

Did you know that for a 10 kg (22 lb) dog, 1 small oatmeal cookie is the caloric equivalent of 1 hamburger or 1 entire chocolate bar for a 5’4″ person?

How about  if a 5 kg (11lb) cat ate just one 28 gram cube of cheddar cheese? That would be the same as if a 5’4″ person ate 3 1/2 hamburgers or 4 whole chocolate bars!

What about if a 5’4″ person ate 3 hamburgers or 2 whole chocolate bars? That would be the same as a 10 kg (22lb) dog eating just 1 hot dog!

burgerNow what about that 5 kg (11 lb) cat again – what if he ate 1 whole potato chip or drank an 8 ounce glass of milk?  That would be the equivalent of a 5’4″ person eating 1/2 a hamburger or 1/2  a chocolate bar for the chip or 4 1/2 hamburgers or 5 chocolate bars for that glass of milk.

It isn’t uncommon for us all to think – awe it is just a little treat.  It can’t hurt, and maybe if it only happened that rare once in a while, it wouldn’t be so bad, however, we need to remember to think of everything in terms of the lesser size our pets are compared to us.  If they are only 1/5 our size (or even less) than that treat that seems small to us, is probably really big for them.

There are certainly health risks that go along with an unhealthy weight.  As the body fat increases, so to does the risk for both cats and dogs on:

  • Shortened life expectancy
  • Diabetes
  • Reduces mobility
  • Arthritis
  • Increased physical injury
  • Respiratory disease
  • Kidney disease
  • Cancer
  • Pancreatitis

and also for cats is an increased risk for:

  • Hepatic lipidosis (Fatty liver which can lead to liver failure)
  • Bladder stones

Now you are probably wondering how you can assess your pet at home to know if they are in the healthy range or heading their way towards unhealthy.  The images (provided by Hill’s Pet Nutrition) below show how your pet looks physically and how that corresponds with each BFI value.

DogsRibsShape from AboveShape from the Side
20Slightly prominent, easily felt, thin fat coverWell proportioned lumbar waistAbdominal tuck present
30Slightly to not prominent, can be felt, moderate fat coverDetectable lumbar waistSlight abdominal tuck
40Not prominent, very difficult to feel, thick fat cover.Loss of lumbar waist, broadened backFlat to bulging abdomen
50Not prominent, extremely difficult to feel, very thick fat cover.Markedly broadened backMarked abdominal bulge
60Not prominent, impossible to feel, extremely thick fat cover.Extremely broadened backSevere abdominal bulge
70Unidentifiable, impossible to feel, extremely thick fat coverExtremely broadened back, bulging mid-sectionVery severe abdominal bulge
CatsRibsAbdomenShape from AboveShape from the Side
20Prominent, very easy to feelLoose abdominal skin, easy to feel abdominal contentsMarked hourglassModerate to slight abdominal tuck
30Not prominent, easy to feelLoose abdominal skin with minimum fat, easy to feel abdominal contentsSlight hourglass/lumbar waistNo abdominal tuck
40Not prominent, can feelObvious skin fold with moderate fat, easy to feel abdominal contentsLumbar waistSlight abdominal bulge
50Not prominent, difficult to feelHeavy fat pad, difficult to feel abdominal contentsBroadened backModerate abdominal bulge
60Not prominent, extremely difficult to impossible to feelVery heavy fat pad; indistinct from abdominal fat, impossible to feel abdominal contentsSeverely broadened backSevere abdominal bulge
70Unidentifiable, impossible to feelExtremely heavy fat pad; indistinct from abdominal fat, impossible to feel abdominal contentsExtremely broadened backVery severe abdominal bulge

One thing for us to remember is that our pets are certainly smaller than us and a little is really a LOT for them.  Reducing their weight even just a little towards the healthy ideal can go a long way in improving your pet’s quality of life and reducing their risk factors for certain health conditions.

If you have concerns about your pets weight, give us a call.  There are diets that are specifically designed to help your pet lose the weight without you feeling like you aren’t feeding them at all.  Many of our staff are trained nutrition counsellors and are here to assist you.