Bulking and cutting: Does this fitness trend really work?

Trigger warning: The following article references a weight loss technique that some readers may find triggering.

If you're regularly found on GymTok or follow fitness influencers on Insta and YouTube, bulking and cutting videos have probably made their way to your social feeds.

This process involves eating more calories than you need, in order to build as much muscle as possible through resistance training over a set period.

Then, you decrease your calorie intake so you're eating fewer than you burn (while adding in cardio exercise) to lose fat.

But while bulking and cutting is common in bodybuilding circles, it isn't designed with long‑term health or everyday gym‑goers in mind. So is it a good idea?

When you exercise, you damage muscle fibres. This is a good thing.

Your body then repairs these fibres by fusing old and new strands together, making them stronger and sometimes bigger.

To increase muscle mass, you must eat more calories than you need to just maintain your current weight, says personal trainer Scott Laider.

But it's not just about how much you eat: what you eat is key.

"A high proportion of these extra calories should come from foods containing protein, which will give you the necessary amino acids to build muscle mass."

But, "there's a genetic limitation to how much muscle mass you can put on over a given time, no matter how much you exercise and eat protein," says medical doctor and personal trainer, Aishah Muhammad.

So if you eat too much, you'll gain fat, not just muscle.

Many of us are already eating plenty of protein. The UK National Diet and Nutrition Survey, external revealed that the average amount of protein eaten by adult men is 87.4g per day and women 66.6g.

That's much more than the British Nutrition Foundation, external recommendation of around 56g for men and 45g for women. Although, if you're active, you may benefit from slightly higher amounts.

Either way, be careful of eating too much – the NHS links a very high-protein, low-fibre diet to recurring kidney stones, external in some people.

It's tough to lose fat without risking that newly acquired muscle.

When you go into a calorie deficit and lose weight quickly, your body can start to break down muscle as well as fat. This means you lose some of the strength gains you made in the bulking phase.

Rugby and athletic coach, Matt Thomas, told us he never recommends a bulk or cut to his players because "across the board this has been seen to have detrimental effects on athletic output."

He explains that both your endurance and strength "generally fall after rapid body weight reduction, although they can be increased with gradual weight loss."

Many average gym-goers want to build muscle without the fat gain that a bulking cycle brings. This process of reducing body fat while increasing lean mass is called body recomposition, external.

"For a lot of people who are looking to build muscle, a 'lean bulk' or a 'recomposition' training phase is the order of the day," says Laidler.

While both methods are slightly different, they both focus on gaining muscle at a slightly slower rate, without the accompanying body fat that a traditional bulk often brings.

"I would advise three total body weight workouts each week, with a modest calorie surplus on training days.

"For the non-training days, if you eat enough calories to break even, or even have a slight deficit, you can avoid adding body fat.

"What you eat really matters. You also need to be eating quality, healthy fats and carbohydrates to help you perform in your workouts as well as recover.

"You'll gradually improve your composition and eventually be in great shape pretty much year-round," concludes Scott.

Slow and steady really does win the race, then.

You can work out roughly how many calories you need to maintain your weight using our calculator below.

Experts recommend keeping a food diary for a few weeks to work out how much you already eat, as it's common to misjudge your calorie intake.

Once you know your maintenance calories, you can then increase them slowly until you see a 1% increase in body weight per month with the right amount of weight training.

While careful bulking and cutting can be useful for professional body builders, it isn't necessary for most of us.

A consistent approach to strength training, combined with a balanced diet, high in protein, and small calorie adjustments is safer and more sustainable in the long term.

Originally published June 2019. Updated March 2026

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