Tackling the problem of fat pets is not as simple as 'eat less, exercise more'. As Dan Chan from the Royal Veterinary College explains the key to successful slimming requires a change of lifestyle for owners as well as their pets.

Our pets' weight problems are usually the result of lack of awareness or the consequences of our own actions. We probably feed them - and in some cases ourselves - too much and don't exercise enough.

Just reducing the amount your pet eats and throwing a ball in the garden for five minutes for your overweight dog is not enough to achieve long-term success. Instead you need to think more broadly about what and when you are feeding them and how they can lead a healthier lifestyle.

Weighing up the problem

The first step is recognising when our pets need to lose weight. Pets weight can creep on gradually (there's no tell-tale sign like clothes feeling a bit tighter to bank on), so it may not be until a routine visit to the vet that you are told your dog or cat has gained a few pounds. Prevention is always better than cure so it's a good idea to monitor your pet's weight on a regular basis.

The vet is also the best person to advise on how much weight your pet needs to lose and what steps are needed to achieve a safe and healthy rate of weight loss.

In the first instance, your vet will usually need to do a thorough examination to make sure there are no serious health problems that could be causing weight gain or may affect a weight loss plan.

Secondly, you will be asked to give a detailed account of what and exactly how much food you feed your pet everyday. Sometimes it's best to simply keep a log of everything you feed your pet for a week and give this to your vet.

Finally, after assessing exactly how much you feed your pet everyday, the vet will be able to help you come up with ways to meet your pet's nutritional needs and at the same time reduce the amount of extra calories. Think Gillian McKeith for animals!

Pets are better off being fed equally measured meals two to three times a day, instead of unmeasured amounts left throughout the day. The exact amount your pet needs is dependent on its breed and size and your vet can help work this out.

Simple steps to success

Fat pets need to reduce their calorie intake in the same way as people do. Cutting out the scraps from the table, which are often the least healthy bits from our meals, such as fatty bits of meat, can go a long way to shifting some of that excess weight.

And having a pet on a weight loss programme doesn't necessarily mean the end of treats. Simple things like using lower calorie treats or even vegetables such as carrots are equally appreciated by most dogsTreats should also be used primarily to reward good behaviour and not just because it's part of their routine or to keep pets from being bored.

Get fit and fabulous!

Exercise is essential part of a successful weight loss programme. Most dogs love the opportunity to run around or enjoy a nice long walk. And unless there are medical conditions that would prevent your pet from increasing exercise, for example severe arthritis or spinal problems, dogs on weight loss programmes need to increase their level of activity.

You could start by simply adding an extra 10-15 minutes to your dog's walk each day, increasing the number of walks per day and gradually introducing activities such as running or fetching toys. In summer months, swimming is a great way to exercise and this may be particularly good for dogs with arthritis.

For cats, increasing activity can be more difficult, but toys can be used to provide some exercise and a great excuse to enjoy a bit of extra feline playtime.

Good results

It's very important to realise that weight loss in pets is definitely possible but it does require hard work and perseverance. A safe and desired rate of weight loss is only 1-2% of the pet's weight per week, so don't expect dramatic changes right away.

The plan designed by your vet may also change several times to achieve the desired rate of weight loss. After starting a pet on a weight loss plan, you will need to attend the weight clinic at your local vet's every couple of weeks just to check on progress. This will allow the vet to determine if further changes are necessary, so don't be surprised if the vet changes the recommended amounts of food a few times. Results can take time, usually a few months to actually notice a difference, but the hard work is truly worth it.

Most owners will notice a much livelier and active pet once the weight starts to drop off - a definite incentive to help your pet to reach its target weight. But it's important to remember that even once a healthy weight is achieved, maintaining it will require sticking to a healthier lifestyle and not letting those old habits creep back in.

Next steps

• Use the virtual weight checker to find out how much your pet weighs and work out its weight loss programme.
• Join a vet-run pet weight clinic near you.
• Get top dieting tips and exercise ideas in the weight clinic.
• Share your thoughts on this feature and experiences of pet weight loss with other pet owners in the forum.
• Read other fat features

Daniel L Chan, DVM, DACVECC, DACVN, MRCVS, is a lecturer and clinical nutritionist at the Royal Veterinary College, London.