Snacking at work: what actually works at a desk

What you eat at work is usually decided before you feel hungry. At four o'clock, the choice is often between what is already within reach and what the machine in the corridor sells, and the machine is always open. In practice, this is mostly a stocking and portioning problem, not a willpower one.

The short answer

• Stock the drawer, not the intention. Dry foods that keep for weeks without a fridge include unsalted nuts, seeds, roasted chickpeas, plain oatcakes and dried fruit.
• Weigh once, not daily. A 30 g portion is the figure UK guidance gives for dried fruit, and it is also the handful commonly used for nuts. Either way, it is much smaller than a hand going back into a shared bag.
• The vending machine wins on placement. The rules on where high fat, salt and sugar products sit in England apply to larger retailers, not to a machine in an office corridor.

This is one of our guides to everyday eating. It deals with the practical end of the question: what survives a desk, what a portion weighs, and what to do about the gap between lunch and getting home.

Why is four o'clock the difficult bit?

Mostly because of timing. A lunch at half past twelve and a dinner at seven leaves six and a half hours, which is longer than the gap between breakfast and lunch. For many people, that stretch is also spent sitting still, looking at something tedious on a screen.

The afternoon dip is often talked about as if it were fixed and universal. The more honest version is that early-afternoon alertness is affected by circadian timing and by how much sleep someone had, and the size of any dip varies a great deal between people. The more reliable part of the story is simpler: a long gap without food, followed by a corridor full of confectionery.

Lunch matters too. We cover that in more detail in our piece on nuts and blood sugar. UK dietary advice builds meals around starchy fibre-rich foods with some protein and some fat, as set out in the Eatwell Guide.

What keeps at a desk without a fridge?

Most useful options are dry. Anything that needs chilling is a different problem. The Food Standards Agency's advice on chilling food safely is that it belongs in a fridge set to 5°C or below, which a desk drawer in an office in July is not.

Storage temperatures follow Food Standards Agency guidance. Portion weights are explained in the next section. The salt and sugar column is there because front-of-pack traffic-light labelling is designed to be read quickly, and the government's labelling guidance sets out how those colours are worked out.

Nuts come up first in almost every version of this question. Whether they deserve that reputation is a longer argument than it looks, and we set it out in are nuts actually healthy.

How big is a sensible portion?

This is where desk snacking often goes wrong. A bag shared with a room disappears faster than anyone intends, and nobody is counting. The reference points below are the ones UK and European bodies publish for adults.

Two points follow from that table. First, dried fruit counts towards 5 A Day at 30 g, which is a small handful rather than a bowl, because drying concentrates the sugars into a much smaller volume. It is also the one item here the NHS is cautious about as a desk snack: because dried fruit is high in free sugars and sticks to teeth, NHS advice is to eat it as part of a meal rather than graze on it between them.

Second, the caffeine figure matters at a desk because the afternoon snack is often a coffee with something alongside it. The EFSA opinion covers healthy adults rather than everyone, and sets a lower figure of 200 mg a day in pregnancy.

That same 30 g is the British Heart Foundation's dried fruit portion — about a heaped tablespoon of raisins, or three dried apricots. For nuts, 30 g is a widely used handful rather than a figure with a formal UK recommendation behind it; the British Dietetic Association's food fact sheets are the most reliable free source for portion questions of this kind.

Does portioning in advance help?

The mechanism is simple enough. If a kilogram bag sits open on a desk, the portion is decided by the hand. If the same kilogram was split into 30 g amounts on a Sunday, the portion was decided once, by someone who was not hungry at the time.

The evidence for portion-size effects on how much people eat is reasonably consistent in short studies, and much thinner over months and years in real workplaces. It is best to treat decanting as a useful bit of friction rather than a rule with a strong outcome behind it. The wider question of whether any of these changes stick is the subject of our guide to changing snacking habits.

A practical version, without pretending there is a trial behind it: buy the plain version, split it the day it arrives, keep one portion at the desk and the rest out of sight, and keep something in your bag for the commute so the station is not the decision point either.

Why does the vending machine win by default?

Because it is the only option that needs no planning at all, and because placement does much of the work. Since October 2022, regulations in England have restricted where products high in fat, salt or sugar can be placed in qualifying shops — checkouts, store entrances, aisle ends and their online equivalents — under the location and volume price rules. Workplace machines and canteens largely sit outside that, so the corridor is, in effect, an unregulated aisle end that is open at four o'clock.

That is not an argument against ever using it. It is an argument for noticing that the choice was shaped by a planogram rather than by appetite.

What does the evidence not show?

Quite a lot, and it is worth saying so plainly.

There is no good evidence that any particular desk snack improves afternoon concentration or work performance in healthy adults. Studies on food and cognitive performance tend to be small, short and run in conditions that do not resemble an office, and the results do not point in one direction. Anyone claiming a specific nut makes you sharper at four o'clock is ahead of the data.

Nor does the evidence settle whether snacking between meals is helpful or unhelpful overall. The literature is mixed, largely because the word "snacking" covers both an apple and a family bag of sweets, and studies rarely separate the two.

What is better supported is much duller: total intake over a day matters more than the timing of any one item, and free sugars, salt and fibre have national targets attached to them because populations sit a long way from them. That is the level at which this advice is reasonably firm, and we say more about how we weigh that kind of evidence in how we write.

Finally, none of this is medical advice. Anyone managing diabetes, blood pressure, a food allergy or any other condition should take snacking questions to their GP or a registered dietitian rather than to a guide like this one; Diabetes UK and the British Dietetic Association both publish condition-specific material that a general article cannot replace.

Where did this come from?

• NHS: the Eatwell Guide
• NHS: how sugar in our diet affects our health
• NHS: salt in your diet
• NHS: how to get more fibre into your diet
• NHS: 5 A Day portion sizes
• EFSA: caffeine
• GOV.UK: restricting promotions of products high in fat, sugar or salt by location and by volume price
• GOV.UK: front of pack nutrition labelling guidance
• Food Standards Agency: how to chill, freeze and defrost food safely
• British Heart Foundation: healthy eating
• British Dietetic Association: food facts
• Diabetes UK: eating with diabetes