Does Intermittent Fasting Actually Work?

Hi,

Before we get into it, just a quick heads up. We're renaming the newsletter to The Fundamentals. It better reflects what we're actually doing here: cutting through the noise and getting the basics right. Same content, same approach, better name. Now let's get into it.

Does Intermittent Fasting Actually Work?

It was the biggest diet trend for years. Now it's falling out of favour. Here's what the research actually shows.

For the last five years, intermittent fasting was everywhere. Every fitness influencer swore by it. Every second client asked me about it.

Now it's quietly dropped out of the top diet trends for 2026. So was it ever worth the hype, or were we all just skipping breakfast for nothing?

P.S. I've built a free calorie calculator and a 30-day fat loss blueprint. [Get free access here.]

WHAT INTERMITTENT FASTING ACTUALLY IS

Intermittent fasting (IF) is an eating pattern where you cycle between windows of eating and not eating. The most common approaches are 16:8 (eat within an 8-hour window), 5:2 (eat normally five days, restrict heavily on two), and 4:3 (three low-calorie days per week).

It's not a diet in the traditional sense — it doesn't tell you what to eat, only when.

WHAT THE SCIENCE SHOWS

The clinical data is actually solid — but not for the reason most people think.

A 2025 study published in the Annals of Internal Medicine found that 4:3 intermittent fasting produced 7.6% body weight loss at one year, compared to 5% in a standard calorie restriction group. A recent meta-analysis showed IF reduced body weight by an average of 3.7kg and improved lipid profiles in overweight adults.

But here's the key finding across nearly every major review: intermittent fasting produces comparable results to standard calorie restriction when total energy intake is matched. In other words, it works, but not because of the fasting window itself. It works because it helps some people eat fewer total calories.

There's no metabolic magic. No special fat-burning state. It's a scheduling tool that makes a calorie deficit easier for certain people to stick to.

THE REAL RISK: MUSCLE LOSS

This is where it gets important.

A 2024 study tracking time-restricted eating participants found that 65% of the weight they lost came from lean mass — more than double what's considered normal. That's not fat loss. That's muscle loss.

Why? When you compress your eating window, it becomes harder to hit adequate protein across the day. Fewer meals means fewer opportunities to trigger muscle protein synthesis, which responds best to 25–40g of protein spread across 3–4 meals.

The research is clear: IF combined with resistance training and sufficient protein can preserve muscle. Without those two things, you risk losing the very tissue that keeps your metabolism running and your body functional long-term.

THE MYTH: "FASTING PUTS YOU IN FAT-BURNING MODE"

Your body doesn't have a switch that flips between fat-burning and fat-storing based on meal timing. Fat loss happens when total energy expenditure exceeds total energy intake over days and weeks, not hour by hour.

What fasting does do is remove decisions. Some people find it easier to skip breakfast and eat two larger meals than to portion-control across four smaller ones. That's a genuine behavioural advantage — but it's about adherence, not metabolism.

If skipping meals makes you hungrier, leads to overeating later, or leaves you under-fuelled for training, it's working against you, not for you.

WHAT I ACTUALLY THINK

Intermittent fasting is a tool. For some people, it simplifies their day and helps them stay in a deficit without counting calories. For others, it leads to under-eating during the day and bingeing at night.

The questions that matter more than "should I fast?" are:

If fasting makes your nutrition easier, use it. If it makes it harder, stop. The best diet structure is the one you can actually maintain.

See you next week,

Gabriel
Nutrition Coach