Is the 6pm eating rule a total myth? Nutritionist reveals the truth about late-night dinners and weight loss

The clock strikes six, and across the UK a huge swathe of dieters mentally step away from the fridge. It’s a rule ingrained in many people as the ultimate sin – eating after 6pm has achieved as much notoriety as a bag full of biscuits when it comes to causing weight gain.

Intermittent fasting is championed by celebs and scientists alike and usually involves setting an early cut-off time for food, putting late-night snacking firmly on the weight-gain hit list.

Imposing rigid eating windows to aid weight loss has led hopeful dieters to believe that any morsel swallowed after sunset goes straight to their waistlines.

However, nutrition expert Emma Bardwell insists that this on-trend belief deserves a reality check.

Nutritionist Emma Bardwell says that eating after 6pm doesn't stop you losing weight.

'The idea that eating after 6pm automatically makes you gain weight is far too simplistic,' Emma says. 'Your body doesn’t suddenly start storing everything you eat as fat when the clock strikes six. For weight gain, the biggest factor is still your overall energy balance. If you regularly consume more energy – calories - than your body uses, you’re likely to gain weight, whether those excess calories are eaten at 11am or 9pm. Equally, you can eat dinner after 6pm every night and still lose weight if you’re consistently in an energy deficit.'

Emma, creator of The 30g Plan and author of several nutrition bestsellers, says that forcing a strict eating deadline is simply unworkable for the average household.

Practically, a 6pm rule makes very little sense,' she says. 'Someone who goes to bed at 9pm has a completely different daily rhythm from someone who works late, exercises in the evening and goes to bed at midnight. It is also important to note that for many people their evening meal is the one they eat socially with family and it would be unwise to miss this just because it doesn’t fit the 6pm rule.'

Despite the myth of the magic deadline, science does show that timing can play a subtle supporting role in our health goals.

‘There is an interesting bit of nuance, though,’ says Emma. ‘While 6pm itself isn't a magical metabolic deadline, there is growing evidence that when we eat may have some effect on appetite, glucose metabolism and weight regulation. We have an internal circadian clock and our metabolism isn't identical at every hour of the day. Generally, we appear to handle food a little better earlier in our biological day than very late at night.'

Looking at recent clinical research, she says that the advantages of early eating are minor at best.

Clinical research shows minimal evidence for the advantages of eating early.

'A 2024 systematic review and meta-analysis of 29 randomised trials found that shifting more calories towards earlier in the day was associated with slightly greater weight loss. But the important word is slightly. Earlier calorie distribution was associated with around 1.75kg more weight loss, and researchers rated the certainty of the evidence as low. They concluded that the effects of meal timing were small and their clinical importance uncertain.'

Other laboratory trials have explored what happens when meal times are put back, uncovering a clear shift in how our bodies manage hunger.

'There's also some experimental research into what happens when identical meals are shifted later,' Emma says. 'In a small, controlled crossover study of adults who were overweight or living with obesity, researchers kept calories, diet, activity, sleep and light exposure consistent and simply changed when participants ate. Later eating increased hunger, altered the hormones leptin and ghrelin in a direction that favoured greater hunger, and reduced waking energy expenditure. So I wouldn't say meal timing is completely irrelevant. But it’s unlikely you’ll gain weight because you ate dinner at 7.30pm rather than half past five.'

Instead of complex metabolic shifts, Emma says the primary reason late dinners trigger weight gain comes down to basic human behaviour and late-night snacking.

'One of the simplest explanations for the association between late eating and weight gain is also that evening calories are often snacks and added calories,' Emma warns. 'Let’s face it, most of us aren't sitting on the sofa at 9pm eating an extra plate of broccoli because we're ravenous. It's biscuits, crisps, chocolate, wine, ice cream. You're also more likely to be tired at the end of the day, which can make eating decisions harder, particularly if you've under-eaten earlier. Someone who has skipped breakfast, grabbed a tiny salad for lunch and tried to be good all afternoon may understandably find themselves raiding the biscuit barrel before bed. I see this a lot in clinic with my clients.'

For those attempting to balance realistic schedules with healthy habits, Emma recommends focusing on core meal structures rather than watching the clock.

Emma says it's better to place emphasis on realistic schedules rather than watching the clock.

'For most people I'd suggest eating regular, balanced meals containing decent amounts of protein and fibre throughout the day, rather than saving the majority of their calories until late evening,' Emma says. 'If you can eat dinner a couple of hours before bed and that works with your lifestyle, great. But if work, children, commuting or evening exercise mean you don't eat until 7.30 or 8 o’clock, I honestly wouldn't lose any sleep over it.’

There may also be reasons other than weight to avoid eating a huge meal immediately before bed, though. Some people find late eating can affect their sleep or exacerbate reflux.

Emma says that ultimately, overall daily choices will dictate dieting results over any arbitrary evening cutoff.

'In short, eating after 6pm doesn't make you fat. There is some evidence that our bodies may benefit from eating more of our energy earlier in the day and less very late at night, but the effect appears relatively modest. Your overall diet, calorie intake, protein, fibre, food quality, movement and sleep matter far more than whether dinner was served at 5.55pm or 6.05pm.'