Why carnivore and keto diets won’t solve your weight problem – a coach’s honest take

Qualified nutitionist and fitness expert Cillian McCahey exposes dieting myths

I had a client recently, let’s call her Sarah, who was absolutely convinced that carnivore or keto was going to be her answer.

She’d seen the transformations on Instagram. She’d watched the TikToks. She was ready to commit. No carbs, just meat and fat. Fast results. Problem solved.

Except it wasn’t.

Here’s what actually happened: Sarah would last 3-4 days eating nothing but steak, eggs and butter. Then she’d crack. Not just a little crack, a full-blown binge on all the sweets, snacks and treats she’d been depriving herself of. The guilt would kick in, she’d swear to “get back on it” Monday, and the cycle would repeat.

Sound familiar?

After working with over 1,000 clients since 2017 and holding qualifications including a BSc in Health Science & Physiology, BSc in Nutrition, and MSc in Sports Nutrition & Exercise, I can tell you this with absolute certainty: extreme diets like carnivore and keto aren’t your problem, and they’re definitely not your solution.

The Cycle You’re Stuck In

Sarah’s pattern is the same one I see with dozens of clients before they come to me:

Monday-Wednesday: Restrictive diet (keto, carnivore, 1200 calories, whatever the latest trend is)

Thursday-Sunday: Complete derailment (biscuits, chocolate, takeaways, wine)

Repeat every single week.

The weight goes down a kilo, then up two kilos. You feel like you’re “trying so hard” but getting nowhere. You blame yourself for lacking willpower.

But here’s the truth: it’s not a willpower problem. It’s a system problem.

Why Extreme Diets Fail for Real Life

Let me be blunt: For most Irish women juggling a career, kids, a social life and normal human responsibilities, carnivore and keto is a disaster.

Here’s why:

1. They Don’t Fit Your Lifestyle

You’re not going to stick to an all-meat diet when you’re making dinner for your kids. You’re not going to avoid carbs at your best friend’s birthday meal. You’re not going to explain to your mam why you can’t eat her potatoes at Sunday dinner.

These diets require a level of control and isolation from normal life that most of us simply don’t have.

2. They Create All-or-Nothing Thinking

You’re either “on” keto (white-knuckling through cravings, avoiding social events) or you’re “off” keto (eating everything in sight because you’ve been so restricted).

There’s no middle ground. No flexibility. No sustainability.

3. They Ignore the Real Problem

Sarah didn’t have a “too many carbs” problem. She had a structure problem. A habits problem. A mindset problem.

She’d come home after a 10-hour workday, exhausted and starving, with no meal prep done and no plan in place. Of course she was reaching for quick, easy, comforting foods.

Telling her to eat only meat didn’t address any of that.

What I Told Sarah (And What You Need to Hear)

After weeks of watching Sarah repeat this cycle, I had to have a straight conversation with her.

“Look,” I said, “we can keep trying different extreme diets every week, or we can actually fix the problem.”

The real work isn’t choosing between keto and carnivore. The real work is:

Building a Nutrition Structure That Fits YOUR Life

Not your favourite influencer’s life. Not some fitness model’s life. YOUR life.

That means:

• Meals you can prep in 20 minutes or less
• Foods your family will actually eat too
• A plan that works around your work schedule, not against it
• Flexibility for weekends without it derailing everything

Fixing Your Habits First

Before you even think about a fat loss phase, you need to sort your foundations:

• Can you consistently eat 3 meals a day?
• Do you have a grocery shopping routine?
• Can you go to bed at a reasonable time?
• Are you managing stress without using food?

If the answer to any of these is no, diving into an extreme diet will only make things worse.

Addressing Your Mindset

Why are you reaching for extreme solutions? What are you trying to fix quickly? What’s driving the urgency?

Usually, it’s one of two things:

1. You don’t believe slow, sustainable progress will work (it will)
2. You’re trying to undo years of damage in 3 weeks (you can’t)

The Boring Truth About Fat Loss

Here’s what actually works, and I know it’s not sexy:

High-protein, high-fibre, nutrient-dense foods. Chicken, fish, lean beef, eggs, rice, potatoes, vegetables, fruit. Meals that keep you full and give you energy.

Consistency over perfection. Six good days out of seven. Not seven perfect days followed by seven terrible ones.

Structure over motivation. A meal plan you can actually follow. Weekly check-ins. Accountability that doesn’t let you off the hook.

Patience. Losing 0.5-1kg per week. Not 5kg in the first week followed by regaining it all plus more.

Sarah eventually listened. We ditched the carnivore experiment. We built her a structured meal plan with carbs (yes, carbs), protein at every meal and foods she actually enjoyed eating. We addressed her habit of coming home starving with no plan.

She lost 12kg in five months. More importantly, she’s kept it off because the approach was sustainable from day one.

Stop Going in Circles

If you’ve tried keto three times, carnivore twice, intermittent fasting, juice cleanses and you’re back where you started (or heavier), please hear this:

The diet isn’t the problem. Your lifestyle, habits and mindset are.

Spend time building foundations. Create a nutrition structure that fits your actual life. Work on your relationship with food. Address why you keep reaching for extreme solutions.

Then – and only then – will fat loss actually stick.

The quick fix you’re chasing doesn’t exist. But the long-term solution you need absolutely does.