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My Patient is not losing weight


What should I do?

This is a question we receive regularly on the Hill’s Helpline. It often requires some sleuthing to figure out the problem. Let’s take Toby. Toby is a male neutered beagle that is currently 15kg and a BCS 8/9 that is not losing weight as expected. Here are some of the common questions we will ask…

Have you calculated Toby’s ideal body weight?

Often it is human error in calculating the target body weight (TBW) that I have found to be the culprit. Occasionally I will get someone who has not calculated TBW at all and has just aimed for a couple of kilos (just take Toby for example). They would target a 12kg body weight rather than the 9kg he should be. It is really important to calculate ideal body weight as accurately as possible otherwise we are just “feeding the fat” of the pet resulting in slow weight loss or no loss at all!


Using the above example of Toby and feeding with Hill’s™ Prescription Diet™ Metabolic


Target body weight: 9kg – he would receive 115grams (1.4 cups) of Metabolic per day



Target body weight 12kg – he would receive 143 grams (1.7 cups) of Metabolic


That is a difference of 25% EXTRA calories! No wonder Toby hasn’t lost  weight.


This is where using the Hill’s Healthy Weight Protocol is very helpful. Morphometric measurements have been shown to have the most accurate estimation of TBW. Second only to DEXA scanning, followed by using the Body Fat Index Charts and lastly, Body Condition Scoring.

Morphometric measurements

Have you checked (and checked again) how much food the patient is receiving?

Another common issue is that the owner is not measuring the food with a standard measuring cup. A large mug is not the best cup to use but I have found pet owners using them! Pet Parents are often overestimating the amount they need. Let’s face it 1.4 cups is hard to measure accurately. In these cases I recommend they weigh the food, or switch to wet food. Wet food is harder to hide from overestimations. This is particularly important for cats where accurately measuring ¼ cup twice a day is difficult. Another great trick is to cut the measuring cup at the level required by the pet.  Also check the pet is not receiving food from other members in the family or from next door.

Have you asked about treats?

This is one of the most common reasons the pet is not losing weight. It is really surprising how many owners don’t consider treats contributing to their porky pet’s curves.

For example, if Toby gets a piece of toast at breakfast, considered an insignificant morsel by pet owners, this contains around 90kcals, an additional 25% of calories to his day!

Beagle sitting down

How much weight has the pet lost?

It crops up from time to time that the pet is in fact losing weight at an appropriate rate. Ideally we aim for the pet to lose 1-2% of starting body weight per week. So if we are looking at a cat that is currently 6kg with a target weight of 4kg she should be losing 60-120grams per week. This equates to 260- 520 grams per month. So… it is going to take 4-8 months for her to reach her ideal weight.

Pet still not losing weight?

Please call the Veterinary Consultation Service on 1800 800 733 (NZ 0800 344 557). One of our veterinarians can help your patient shed some pounds.

Dr Danielle Page, BVSc, Bcomm, Hill’s Technical Services Veterinarian with Rosie.

Danielle completed a Bachelor of Commerce from Sydney University in 2003, she decided to pursue a veterinary degree and graduated from Massey University in 2008. She worked as a small animal veterinarian in Canberra, ACT and then Florida, USA for four years. In 2012 she became the Technical Services Veterinarian for Florida for a veterinary nutrition company and then subsequently, Clinical Trials Manager for the USA. In 2014 she moved back to NZ with her family and joined the Hill’s Professional Veterinary Affairs team and is the Hill’s Technical Services Vet for NZ.

Dr Danielle Page