And forget about a sausage roll and fizzy drink the next day. "That's when you guzzle coconut water and do a 10am yoga class."
The Americans, of course, have a term for this - healthonism. It's a blurring of health and hedonism, of priming for - and erasing - the sins of the night before with gym workouts and cold-pressed juices.
Lucie Green, Worldwide Director of trend forecasters JWT Innovation Group, who first identified the healthonist movement, refers to it as "mindful partying".
"Alcohol, partying and dance are no longer seen as mutually exclusive to healthy living," says Green. "We're now putting healthy habits alongside fun in a have-it-all-way."
Lily, 30, rolls her eyes at the term healthonism. She's been living like this for years. "It's pretty simple really - I've made the choice not to give up one aspect of my lifestyle for another, so if I eat right and exercise five times a week then it's okay to have some drinks or a few lines of coke every now and again."
Lily is vague about what she does for a living ("Advertising," is all she'll say, with a wave of her hand), but a Kingsland gym is her happy place.
"I work hard during the day and I work hard most evenings to achieve the body I have. So why shouldn't I put on a tight dress and go out dancing?"
The key, it appears, is balance. "I know it sounds boring, but it's all about mindful moderation. If it's going to be a big night, I'll do a boxing class to sweat it out. I'll also watch what I eat, staying away from carbs and having lots of salmon or eggs, which are digested more slowly, meaning alcohol is absorbed more slowly into my system."
The former model also avoids sugary cocktails and alternates glasses of red wine with water. The next day, she shuns the usual paracetamol, grease and long blacks, instead busting out the green juice, lunchtime yoga class and turmeric shots, which help to fight nausea.
"Once, after a big night, I had to run out of a Bikram yoga class to throw up. But trying to find the threshold between health and hedonism is important, because both are important to me."
Tony admits he'd never heard of the term healthonism, but agrees it shouldn't be an either/or decision. "If you're hardcore at the gym, that means you can be hardcore at the pub."
Once, after a big night, I had to run out of a Bikram yoga class to throw up. But trying to find the threshold between health and hedonism is important, because both are important to me.
Healthonists in Britain have further blurred the line between exercise and partying, combining the two. London's House of Voga, for example, which combines yoga with the expressive 80s vogueing dance style popularised by Madonna, recently co-hosted a party with a Mayfair nightclub. It started with a one-hour voga class before moving on to drinks and dancing into the wee hours.
Kensington's Equinox health club also hosts regular night-time events where members are treated to a range of different yoga classes, with guest instructors, DJs and cocktails.
The drinking-while-exercising mash-up hasn't quite made it to these shores yet, but many healthonists believe an intense workout can be rewarded with copious amounts of alcohol.
A 2015 study published in the journal Health Psychology found that people tend to drink more than usual on the days they engage in more physical activity. Researchers found respondents were inclined to push themselves harder during a workout when the reward was a few bevvies.
Dr Toby Mundel, Massey University senior lecturer in Science and Exercise, isn't convinced we've got that right. "If you binge-drink after a heavy exercise session, you can actually slow down your recovery," he says. "Several studies have shown that when you work muscles hard during a workout, such as a hard resistance session where muscle damage occurs, and then binge-drink afterwards, the force/strength you lose is greater and recovery is delayed for more than two days.
"It's thought that alcohol reduces the neural drive to the muscles [from the brain] and may also affect recovery of the damaged muscles themselves."
Mundel also doesn't buy the idea of "sweating out" toxins the next day, saying the liver has a set rate at which it gets rid of things like alcohol and drugs. "Nothing you do after your big night can speed that up that metabolic process, only time will do that. It doesn't hurt, however, to have a good meal before you begin partying, to line the stomach, which assists alcohol to be cleared."
Healthonists who believe a workout the day after helps them to bounce back more quickly may also be barking up the wrong treadmill.
"It's different for everyone, but if you can handle a light workout then it might make you feel better mentally but it won't help physically because your body is still under pressure to get rid of toxins from the night before," says Mundel.
In fact, if you're dehydrated from drinking, then an intense exercise session could make you even more dehydrated, which could eventually lead to an increase in blood pressure and heart problems.
"The general rule of thumb is to wait 24 hours after a big night before you exercise, to give your body time to rest and recuperate," advises Mundel.
Les Mills personal trainer and nutritionist Emma Brake is another who won't admit to being a fan of the healthonist trend, saying she'd never advise clients to prime themselves for a night out with a tough workout. Or to come back the next day to atone for their sins.
"Healthonism is becoming more noticeable because people think they can burn off as many calories as they're going to consume that night," says Brake, who recently also opened Sweet7, a Ponsonby physio/personal training/nutrition studio.
"But it's much more complex than just 'energy in, energy out'. What's far healthier and sustainable is to stick to the 80/20 rule: go out and have a glass of wine and dessert, because you're only human and denying yourself is no way to live. But make sure you also move - and move every day, not just because you want to try to burn off the empty calories of alcohol and processed food that you're going to consume later, but because you actually enjoy it."
