We’ve Got All The Reasons Your Coffee Might Be Making You Fat

Yep, we know what you're thinking – please don’t ruin the one and only vice remaining to me. And while we hate to be the bearer of bad news, that coffee habit of yours could well be helping you to pack on the pounds. Here's how.

cup of coffee and roasting beans

Oh, we adore our morning brew, our mid-morning pick-me-up, our post-lunch livener… what’s that? We’re drinking too much coffee? Puh, no way. Okay, so we might be slightly concerned, but surely, apart from all that pesky lying awake at night not being able to sleep, coffee is grand? Not so, says nutritionist Lyda Borgsteijn, who reckons it might actually be adding sneaky pounds to our frames we had no idea were creeping on there. And to think we were blaming that on family-size bags of Tayto.

It’s all to do with not just the extra milk, sugar and syrup, but how our bodies process caffeine. And, er, one other thing. “Let’s face it, how many of us fall privy to more than just coffee,” Lyda says. “What about the scone, the croissant, the brownie slice…” Guilty as charged, yer honour, sir.

Here, Lyda gives her take on how coffee can pack on the pounds, and the ones to buy if you really can’t give up your fix, as well as what to definitely avoid.

The stress/coffee conundrum

First things first, before you even take into account all that sugar, full fat milk and pumpkin spice syrup you’re adding (go on, we know you love it), caffeine itself can cause weight to spike. Say what? Cortisol’s the culprit, says Lyda. “It’s a hormone produced by the adrenal glands which can increase blood pressure, spike blood sugar and create stress in the body in preparation for the ‘fight or flight response’,” she explains. “Depending on how often you drink coffee and at what time of the day, your cup may impact your hormone balance and therefore impact your weight.” Uh-oh.

It gets worse. “Studies in humans have shown that caffeine increases cortisol and epinephrine at rest, and that levels of cortisol after caffeine consumption are similar to those experienced during an acute stress. Compounding the problem, people tend to consume more caffeine during stressful periods,” she explains.

The constant release of cortisol, our star of the hormonal show, eventually causes major functions in the body to shut down or operate at only a subpar level – immune function, digestion, endocrine function. Cortisol sets off an increased rush of glucose from your tissues (including breaking down muscle tissue to make glucose). This is all because of the anticipation of the energy which will be needed for the ‘fight or flight. Do this again and again, day after day, and Insulin resistance ensues eventually. Alongside this, cortisol also signals to your body to store fat, especially around the abdominal area,” she finishes.

Lyda says that when you take the typical Irish, high-in-carbs diet (hello, spuds), couple it with mucho stress and lots of coffee, we’re a recipe for caffeine-based weight gain disaster. “The overarching point is that the poison is in the dose. For those of us drinking coffee all day, leading sedentary lifestyle, eating a poor diet and always under chronic stress – well you have the perfect storm right there,” she points out.

So, what can we do? Limit our dosage, of course – the recommended RDA is 400mg, around four small cups of coffee – and make careful choices about the sorts of caffeine-based drinks we’re buying so we don’t get all those extra calories, which can compound the weight-gain problem.

If you’re now dead set on giving it up why not use the last bit off coffee you have as an exfoliator, or even as a shampoo? We tried it out and had some surprising results.

Argh! What can I drink!?

Here’s the list from okay to OMG – stay away.


A grande americano comes in at around 40kcals, with three shots of expresso, depending where you buy,” says Lyda. That delivers around 320mg caffeine – almost your daily RDA. If you add milk and sugar, you’re adding extra calories – about 20kcal for milk and 40kcal for every teaspoon of sugar. “These add up very quickly especially if you’re indeed a true addict and consume a few cups a day,” she [points out.

Skinny latte

Beyond the americano, the next best thing is the skinny latte, with 190kcals,” Lyda reveals. Don’t think it sounds too bad? “Have you ever considered it’s equivalent to eating a Cadbury’s Crunchie bar?” she asks. Ugh!

Flat white and cappuccino

Even so called ‘better’ choices of coffee like cortado, espresso, flat white, cappuccino and breve can still pack an average 130-220 kcals (depending on amount of milk) per cup and we then do a great job at piling on the sugar with extra pumps of flavouring, sugar and chocolate flakes,” Lyda says. Avoid this like the plague: “A few pumps of caramel flavouring, and you’ve added 5 teaspoons of sugar,” she says. It’s scary stuff.

Double caramel macchiato

A 16oz skinny variety comes with 240kcals,” warns Lyda. And here’s where the horror really hits home – it’s got 31g of sugar. “Remember, we’re advised to eat just 7tsp of sugar per day or about 28 grams… so your caramel macchiato just bought you your day’s intake of sugar, along with a guaranteed sugar crash later in the morning.”

Bulletproof coffee

Nope, says Lyda, this isn’t the magic, er, bullet either. “The new paleo trend, it’s a mix of butter, MCToils [e.g. coconut oil] and coffee,” she explains. We’re told it’s a wonder for making us go, go, go in the morning. “But the coffee still packs circa 300-400kcals of fat, which is a lot of extra calories,” she says.

Grande frappucino

The coffee menu has really branched out and things like a chocolate whip frappuccino, mocha frappuccino, non-fat tazo chai latte iced tea threaten your waistline. A typical grande frappuccino packs around 410kcals and 66grams of sugar,” Lyda says. “Not only is that nearly as many calories as a main meal, but the amount of sugar is colossal – 16 teaspoons of sugar in one glass.” Yikes.

However, if you just can’t part with your beloved skinny latte, why not try out our top five spots for a delish cuppa?