The Weight That Wouldn't Budge

It's ok, it happens to many of us, including myself.

I remember it very clearly. One day Jessie was a fit and lean young dog, and then, poof, she was overweight. Well, not really. But it definitely snuck up on us.

To help her lose the weight, I did what I thought were the most logical things:

I decreased the amount of kibble I fed her.

I increased her exercise

I switched to a weight loss kibble

Yet the weight wasn't coming off. I was stumped. What was I doing wrong, and why couldn't I help Jessie lose the weight?

No matter what I tried, nothing worked. What about you? Have you been in these shoes, left more confused than ever about how to help your dog lose weight?

The One Job Your Dog's Food Has to Do First

Let me be the first to raise my hand and say it took me a few years to really understand this concept, and it changed how I look at diet, food, and nutrition, not just for Jessie, but for my clients' dogs too.

Your dog's primary reason for eating is to meet their energy needs.

It's not for taste. 

It's not for boredom. 

It's not for nutrients. 

It's not for fibre.

Plain and simple, it's for energy. Because without energy, your dog can't do the basic things in life.

Every biological process in your dog's body, like sleeping, eating, digesting, breathing, relies on a steady supply of energy.

Energy and nutrition are inseparable. You can't meet one without considering the other. The amount of food your dog consumes must meet both their energy and their nutrient needs.

The Building Blocks That Double as Fuel

Energy in your dog's diet comes from three sources: 

Protein, 

Fat, and 

Carbohydrate. 

The macronutrients.

In addition to being building blocks, they're fuel. Once eaten, they're digested, absorbed, and carried through the body, where they're converted into the energy that powers every cell.

Sounds straightforward, right? Feed your dog a mix of these three and they'll thrive. Not exactly. There's a bit of science mixed into all this.

Why comparing food by the cup can mislead you

Not all food is created equal. That's pretty obvious with pet food, and the endless debate about what to feed your dog. This isn't about the type of food, or the marketing that surrounds it.

Foods have different levels of energy density — the amount of energy in said food, like a handful of kibble, or a mixture of fresh meat and vegetables.

Let me try to keep it simple.

The denser a food, the less volume your dog needs to eat. 

The less dense, the more volume they need.

Everything in the food that isn't energy, like the vitamins and minerals your dog needs, has to fit into that same volume. Less volume means those nutrients need to be more concentrated to still add up. More volume means they can afford to be more diluted.

So what does that mean for how you actually feed?

When a bag of kibble has you measure by the cup, or a fresh feeder measures by percentage of body weight, we can get into a little trouble. Both ways can be misleading. 

A more accurate way is to know how many calories are in a food, and how many calories your dog actually needs.

I know! Who wants to count calories? I certainly don't. But it's a helpful tool to have. 

Measuring your dog's food by cups or grams alone can be the reason your dog is putting on extra weight.

There's another layer to this too. Self-regulation gets a lot harder when the food itself works against it. Today's commercial food, in particular, is made to be more palatable than ever. Add in the reality that most dogs today lead fairly sedentary lives, and it becomes even more important to feed the correct amount for your dog.

The 2 Letters Hiding on Every Pet Food Label

Not all the energy in your dog's food actually makes it into your dog. Some get lost before it's ever used.

There are three types of energy worth understanding when it comes to your dog's food:

Gross Energy (GE) — the total energy in a food.

Digestible Energy (DE) — Gross Energy minus whatever comes out in the faeces.

Metabolisable Energy (ME) — Digestible Energy minus whatever's lost in urine.

ME is the energy that's actually used by the body. 

When you look at a pet food label, ME is typically what you'll find. Not GE. Not DE.

But the ME number usually isn't measured. It's predicted. AAFCO (the organisation that sets pet food standards in the US) has protocols for feeding studies, but most brands use a predictive equation instead, because studies are expensive and labour-intensive to run.

Predictive metabolisable energy (ME) values on pet food labels are estimates, not direct measurements, and studies show those estimates can be wrong in either direction. In one study of dry dog food, the commonly used modified Atwater equation underestimated ME by about 5.3% on average and by as much as 16% for individual diets. That means a pet fed “to the bag” may actually receive more or less energy than the label suggests, depending on how the food’s ME was calculated.

Feed that same food every day, for months, for years it can affect your dog.

This is part of the answer to a question I get asked often: why is my dog gaining weight when I'm feeding exactly what I was told to feed?

Quick note if you're feeding homemade: label requirements for ME generally apply to complete and balanced commercial meals. If you're feeding homemade and sourcing individual ingredients from pet food suppliers, those ingredients most likely won't come with any nutritional value listed at all, which makes this whole ME conversation even harder to have. That's a big enough topic to deserve its own article, but worth flagging here: if commercial labels can be off by 5 to 16%, an unlabelled homemade ingredient is an even bigger unknown.

So, How Much Does Your Dog Really Need?

That's not the only place estimates show up. The label tells you what's in the food, but it doesn't tell you what your specific dog needs out of it. That's a different problem, and it depends on the individual dog. Generic guidelines have their place, but also their limits.

To understand your dog's unique energy needs, start with their Resting Energy Requirement (RER) — this is what a dog needs at rest, under normal conditions. From there, their Daily Energy Requirement (DER) is determined based on life stage and activity:

Growing puppy

Lactating mum

Working dog

Sedentary dog

Senior dog

And so on.

Again, similar to ME, these formulas are starting points. Think of them as guidelines, not absolutes. You work from these numbers, then adjust accordingly. Because what you think of as "active" for your dog may actually sit closer to sedentary, meaning their real DER could be lower than expected.

When you rely on the data, rather than "balance over time" or generic feeding charts, you're setting up a feeding plan that works for your dog, not the one down the street, or even their littermate.

When the Scales Tip Either Way

When a dog takes in more energy than they expend, that's weight gain. Maintaining a healthy weight is far easier than losing it. 

The same goes for the other direction. With a consistent energy deficit, the body reaches first for stored glycogen, then body fat, and eventually stored protein. Weight loss isn't just visible fat loss — it can also be muscle loss.

To maintain balance, energy in and energy out need to roughly match.

You now know more than most dog parents

I've given you a quick deep dive into energy and the role it plays in your dog's weight. You probably know more now than most dog parents ever will.

You know why energy is the first requirement food has to meet

You know where that energy comes from

You understand how energy density changes the amount of food your dog eats

You get that the ME on a bag of food is an estimate, not a guarantee

What you don't have yet is the how. 

How to calculate your dog's specific needs. 

How to choose a food that actually fits — whether the goal is to lose weight, gain it, or hold steady. 

How to adjust as life stage, activity, or body condition shifts.

You can’t Google your way out of that knowledge. Luckily, it's the exact work I do with dog owners in my 1:1 coaching programmes. I build a feeding plan around your dog's real numbers, not a generic chart.

Let's get your dog's numbers sorted. Book a call →