What’s a new year resolution that is:

1 Good for the environment

2 Will save you money

3 Will help you lose weight

4 And involves just one small change?

Answer: giving up lattes! You know, those big buckets of brown, hot milk that you need to drink three of each day just to function? Crucially, giving up lattes is not the same as giving up coffee. That is next level. But giving up milk in your coffee can have a big effect on a whole range of areas.

Take the money and calories you’ll save. If you buy three small full-cream lattes a day at $4 a latte, you’re spending $84 a week and adding (at about 130 calories a latte) 2,730 calories a week. Giving up milky coffee is the equivalent of having an extra day of calories spare each week.

Of course if you buy all your long blacks, the financial saving will be cancelled out, but the calorie saving will still be massive.

But black coffee is easier to make at home and transport in a flask than making a cafe-quality latte. You could save close to $4,000 a year by bringing a flask from home, even counting the price of beans.

Then there’s the environmental costs. A recent Guardian article pulled no punches. It called dairy “a disaster” and said: “A glass of dairy milk produces almost three times more greenhouse gas than any plant-based milk.”

Milk substitutes have their problems. Almond milk is bad for bees, rice milk sucks up a lot of water, and large swathes of rainforest in the Amazon have been burned to make way for soy farms. Could the answer just be to go black?

And how easy is it to give up milk in your coffee?

As a descendant of dairy farmers who has enjoyed cow’s milk daily all my life, the task appeared daunting. Week one, and the hardest part was retraining my palate. I made black coffee at home in a plunger (unenjoyable – either too weak or too strong, felt like an incomplete beverage), and then got long blacks or double espressos in cafes when I was out (also unenjoyable, felt wrong). My first double espresso tasted like swallowing a small cup of tar.

Whatever way I made it the coffee was too hot and bitter. First thing in the morning, black coffee seemed harsh and acidic – it burnt my tongue. I missed lattes! Part of it was psychological. I wanted to be lulled into the day with a cup of warm milk (yet paradoxically also woken with a shot of coffee). My milky morning coffee had become such a ritual and going without it felt like a day that got off to a bad start.

I asked Twitter for advice.

Some suggested making the transition slowly via the macchiato road; others recommended milder cold brews.

“Maybe try a short macchiato or just one milk coffee for a few days until you get used to the black stuff. Years ago, I switched to one milk coffee per day. My stomach/digestion was way better & I lost weight – felt like a great thing to do”

Advice for weaning yourself off lattes and flat whites came thick and fast and included adding a bit of sugar to your coffee to remove the bitterness, then gradually cutting out the sugar, or having your coffee with a chocolate.

“Well I don’t know if this is ‘better’ but it will help you associate it with a nice taste – have something sweet with it. Like a Lindt ball or something small. The sweet + bitter is yum and it’s actually the same calories overall as a latte.”

People advised it took between three and 14 days to adjust your palate to black coffee.

By day three I had started drinking a pour-over that I bought in Osaka. The night before I would make a pot of black coffee, put it in the fridge and have a cold brew with ice in the morning.

I don’t know why I found cold brew more palatable, but it seems gentler first thing in the morning than an espresso.

Now, five weeks in, I have become a black coffee drinker. If I have a craving to take the edge off the bitterness, I’ll have a macchiato. But largely the change has stuck.

This week I tried a flat white, just to see what I was missing – it tasted … weird, wrong somehow.

Trading lattes for long blacks once seemed impossible. But five weeks in the transition has gone well. I am saving money, feel less bloated, am consuming fewer calories and have made a lifestyle change that is good for the environment.