Is Intermittent Fasting Worth the Hype? Let's Talk About It

Intermittent fasting (commonly shortened to IF) gets thrown around a lot — and depending on who you listen to, it's either the answer to everything or wildly overrated. So let's cut through the clutter and talk about what it is, what it can do, and more importantly, whether it's actually a good fit for you.

First, a framing shift that matters, intermittent fasting isn't a diet. It's a meal timing strategy. You can run it alongside keto or high carb, as a vegan, a vegetarian, an omnivore, or someone who thinks vegetables are a garnish. The eating pattern is the variable — everything else is still up to you. And for the record, it's something I've personally found useful in the past. That said, I'm not here to sell it to you. I'm here to help you figure out if it belongs in your toolbox or not.

So what are we really talking about?

There are a few different ways people structure intermittent fasting. Time-restricted eating is the most common — you have a daily eating window and fast outside of it. The 5:2 method involves eating normally five days a week and capping calories around 500 on two non-consecutive days. And then there's the 24-hour fast, done once or twice a week.

The version most people mean when they say "intermittent fasting" is the 16:8 — sixteen hours fasted, eight hours eating. You're not necessarily skipping a particular meal, you're compressing when all your meals happen. That window is yours to structure however it works for your day.

Why does it work for some people?

Part of the reason IF took off is that early proponents were selling a very appealing idea — you don't have to change what you eat, just when you eat it, and the weight will come off. And look, for some people, that's not entirely wrong. Having a restricted eating window can naturally reduce calorie intake without anyone tracking a thing. It tends to cut out mindless evening snacking, and eating larger meals within a shorter window can feel more satisfying than grazing across the whole day. Less meal planning, less decision fatigue — it's a lifestyle simplification that a lot of people find they can actually stick to.

From a more physiological angle, there's a decent argument that fasting can support insulin sensitivity and increase growth hormone secretion, both of which play a role in preserving muscle mass. That matters because muscle is metabolically expensive, meaning your body burns more calories just to maintain it. Protect the muscle, and you protect your metabolic rate as you lose weight.

There's also something worth noting for those of us in midlife. During menopause, declining oestrogen tends to drive fat toward the abdomen — the stubborn kind that doesn't shift easily (yay to us!) The theory is that the extended low-insulin state during a fast activates an enzyme called hormone-sensitive lipase (HSL), which helps mobilise fat from those sticky storage sites. Some research has also shown fasting increases blood flow to abdominal subcutaneous fat, which in theory helps shift it. It's not a guarantee, but it's a reason why IF might be worth considering alongside your nutrition changes if you're navigating perimenopause or menopause.

Beyond body composition, the research does show other benefits — improvements in cardiovascular markers, triglycerides, LDL, blood pressure, inflammation, and even some neuroprotective effects. Worth knowing. AND worth keeping in context.

Where it falls apart though

The honest downside isn't that your muscles will waste away or your metabolism will grind to a halt — those fears are largely overblown. You don't need to eat every two to three hours to keep things ticking, and skipping breakfast won't doom you.

The real issue is much simpler - calories and macros still matter. Intermittent fasting is not a workaround for poor nutrition. You can absolutely overeat in an eight-hour window. And if you're trying to hit an intake that supports muscle building, some women find they genuinely cannot get enough food in that compressed timeframe without feeling uncomfortably full.

The other common failure point is forcing a pattern that doesn't fit your actual life. If you train first thing in the morning, fasting until the afternoon is a tough sell — and probably not serving your performance or recovery either. If a shortened eating window means you're ravenous by mid-afternoon and overeating by dinner, the framework isn't working for you. 

And for women specifically — the research suggests that premenopausal women may see fewer benefits from fasting than men, and in some cases experience more adrenal stress or muscle mass loss. If you're not someone who naturally skips meals, it's worth easing in rather than jumping straight to a 16:8 and wondering why you feel terrible.

An important note if you're on GLP-1 medications

This is worth its own conversation, because if you're spending any time in GLP-1 communities online — Facebook groups, Reddit threads, TikTok — you'll have seen intermittent fasting recommended constantly as a way to accelerate results. The logic seems straightforward - GLP-1s suppress appetite, IF restricts your eating window, combine the two and you're in a bigger deficit faster. Job done.

Except that's not quite how it plays out, and most dietitians and nutrition professionals (like me) working in this space will tell you the same thing.

The issue is that GLP-1 medications already significantly reduce your appetite and slow gastric emptying. Your hunger cues are already dampened. Layering a restricted eating window on top of that means many people end up eating far too little, not just in terms of calories but in terms of protein. And protein is the thing we absolutely cannot afford to compromise on when we're losing weight on a GLP-1, because the medications don't discriminate between fat mass and muscle mass. The loss of lean muscle on GLP-1s is a real and well-documented concern, and it becomes significantly worse when protein intake drops.

There's also the practical reality of how these medications make people feel. Nausea, early fullness, and general food aversion are common — particularly in the earlier phases or after a dose increase. Restricting your eating window further when you're already struggling to get food in isn't a strategy; it's a fast track to under-fuelling in ways that will affect your energy, your muscle mass, and your long-term metabolic health.

The goal on a GLP-1 isn't just to eat less — it's to eat well within the reduced appetite the medication creates. That means spreading meals across the day, prioritising protein at every sitting, and using the window your appetite allows rather than shrinking it further. For most people on these medications, the focus needs to be on eating enough of the right things, not on finding more ways to eat less.

If you're on a GLP-1 and IF appeals to you — maybe you've been using it for years, or you find it genuinely easier to manage meals that way — it's worth having that conversation with your prescribing doctor or a dietitian who works specifically in this space. Context matters. But if you're considering adding IF because a Facebook group told you it'll speed things up, it's worth pausing on that one.

So who is it good for?

In my work, I use intermittent fasting in two main situations. The first is to help someone reconnect with genuine hunger — a lot of us have spent years eating on a schedule rather than because our body asked for food, and IF can be a useful reset for that. The second is when it genuinely makes hitting their nutrition targets easier. Some people find it simpler to eat three solid, satisfying meals in a window than to plan six smaller ones across the day.

If it fits your schedule, your training, your lifestyle, and your goals — great, use it. If it's something you're forcing because you've been told it's the answer, it'll bite you in the arse eventually.

The bottom line is that meal timing is one variable in a bigger system. Get your calories and macros in line with your needs, and any meal timing that works for your life will get you results. No eating window can compensate for nutrition that isn't dialled in — and a nutrition plan that's dialled in will work regardless of when you eat.

Experiment, pay attention to how you feel, and be willing to shift things as your goals change. What works brilliantly during a fat loss phase might not be what you need when you're trying to build strength or get through a high-stress season. It's just about knowing how to work with your body instead of against it.

XO Jane