"It's normal for dogs to eat less in hot weather" — 2026 Vet Summer Warning: The Signs You Might Be Missing

During a heatwave, it is true that most dogs will eat less. The problem is — how do you know your dog isn't the exception?

 

Every summer, countless dog owners look at the food left in the bowl and say the same thing to themselves: "It's too hot. He's not hungry. It's fine."

 

Most of the time, that thought is right.

 

But what if it isn't?

 

The Met Office is predicting temperatures above 30°C in parts of the UK this summer. Before the heatwave hits, there is one thing worth knowing: Is your dog's lack of appetite normal, or is it a sign that something is wrong?

Why normal and dangerous can look exactly the same

This is the heart of the problem. Dogs cannot tell you they do not feel well. And the way they act when they are sick — not eating, low energy, lying around — looks almost identical to how they act when it is just too hot.

 

Vets warn that this is exactly why dangerous signs get missed. If you assume every loss of appetite is just the heat, what happens when it is not?

 

So how do you tell the difference?

One table: Normal vs needs attention

Save this table to your phone. You will use it all summer.

vs

Normal

Needs attention

Eating less, but still eating some

Has eaten NOTHING for 24 hours

Still interested in treats and toys

Won't even touch their favourite treat

Still has energy, wants to play or interact

Lethargic, sleeping all the time, won't move

Eats more in the cooler morning or evening hours

Vomiting or diarrhoea

Still not eating normally after the heatwave is over

The vet's main advice: If your dog hasn't eaten anything for more than 24 hours, or shows any of the signs above, don't wait another day “just to see.” Call your vet.

Why dogs naturally eat less in summer (the science)

First, the good news. Dogs eating less in hot weather does have science behind it.

 

Digesting food creates heat. When it's already hot outside, a dog's body naturally tries to do less of anything that creates more heat — including digestion. Eating less = creating less heat = staying cooler.

 

One study found that cats eat about 15% more in winter and less in summer. While this study was done on cats, the same seasonal logic applies to dogs.

 

On top of that, dogs are naturally less active in summer. It's too hot to run around during the day. They'd rather lie on the floor and sleep. Less activity means they need fewer calories.

 

A canine nutritionist puts it this way: If your dog is eating less but still has good energy, normal behaviour, and regular bowel movements, you can reduce their food by about 10-20%. Their appetite will usually come back when the temperature drops.

Vet warning: Some dogs are more at risk

Not all dogs handle heat the same way. If your dog is one of these breeds, you need to watch more carefully.

 

Thick-coated breeds — Bernese Mountain Dogs, Huskies, Newfoundland dogs. Their thick fur makes it harder for them to cool down.

 

Flat-faced breeds (highest risk) — Pugs, Boxers, English Bulldogs, French Bulldogs. These dogs already struggle to cool themselves. In hot weather, they are more likely to have breathing problems or heatstroke. A drop in appetite could be an early warning sign.

 

Puppies, dogs with chronic illness, and working dogs should not have a big drop in food intake, even in hot weather. If they are eating much less than usual, speak to your vet.

5 practical tips for feeding your dog during a heatwave

If you are sure your dog is just eating less because of the heat, here are some ways to help them through the summer more comfortably.

 

1. Change feeding times
Feeding a dog during the hottest part of the day makes them more uncomfortable. Move mealtimes to early morning or late at night, when temperatures are lower. Dogs are more likely to eat then, and digestion is easier.

 

2. Change the order of walks
Studies show that a dog's core body temperature continues to rise for a while after exercise. The right order is:

Morning: Feed first, wait 30-60 minutes, then walk

Evening: Walk first, let your dog cool down, then feed

 

3. Reduce portion sizes a little
If your dog's appetite is clearly lower, you can reduce each meal by 10-20%. Keep feeding twice a day as usual. When the weather cools down, go back to normal portions.

 

4. Make frozen treats at home
A simple recipe: pour low-salt meat or chicken broth into an ice cube tray. Add small pieces of your dog's favourite treats, chicken, or vegetables. Freeze. These frozen treats increase water intake, help with cooling, and give your dog something to look forward to on hot days.

 

5. Increase water intake
Dogs dehydrate faster in hot weather. Always have fresh, cool boiled water available. If you feed dry food, add water or switch to wet food. Both are good ways to increase fluid intake. Avoid bottled mineral water — long-term use may increase the risk of urinary stones. Boiled tap water is the safest choice.

A simple home check

If you are not sure whether your dog is in the “normal” or “needs attention” category, go to the vet if at least one of these is true:

 

No food for 24 hours (not “eating less” but “eating nothing”)

 

Not interested in their favourite treat (this is a very telling sign)

 

Clearly low energy — not moving much, not wanting to play, just lying there

 

What vets keep saying: It is always better to make a trip to the vet and find out it's nothing, than to stay home and “wait one more day.” A dog's condition can get much worse in 24 hours.

The bottom line

“It's normal for dogs to eat less in hot weather” — most of the time, this is true. But “most of the time” is not “all of the time.”

 

This summer, when you look at the food left in your dog's bowl, take an extra 30 seconds to check: Is their energy normal today? Are they still interested in treats? Are they eating a little less, or have they stopped eating completely?

 

If it's the first one, don't worry. Use the tips above.

 

If it's the second one, don't wait. Call your vet.

 

Better to make one trip for nothing than to wish you had gone earlier.

Title

References

 

Liverpool University study on seasonal cat food intake, via Pet Corner (2026)

 

Fish4Dogs nutritional lead Ryan Whitman, All Paws Industry (May 2026)

 

The Pet Expert, Canadian Pet Connection (May 2026)

 

DatGud seasonal feeding guide (March 2026)

 

Republic World summer pet appetite guide (May 2026)

Pet Accessories Refrigerator Magnet

Buy 3, get 1 free.  Buy 5, get 2 free.

Buy  it now