The EASIEST EVER guide to perfect portion sizes

We’ve all heard about portion distortion. How much we eat is just as important as what we eat.  Studies show that regardless of hunger level, if people are served more food they’ll eat it. Dietician Claire Donnelly has the easiest guide to getting your portions right we’ve ever seen

However in the long term ginormous portions make it difficult to maintain a healthy weight. This is because we come to regard super-size portions as the norm. Everything else seems a bit puny by comparison. What’s more if we’re moving less and spending increasing amounts of time in front of a computer, we’ll burn fewer calories.

A recent study by the Institute for Fiscal Studies claims that compared to the 1980s, we’re now engaging in less physical activity and eating less calories. However the nutritional quality is poorer, due to a shift during the recession to cheaper, processed foods. That is foods higher in saturated fat and sugar. It was also highlighted that adults are typically eight kilograms heavier than they were at the start of the 1980s.

One factor in the bulging waistline equation is undoubtedly portion sizes. But let’s face it they’re as varied and confusing as women’s dress clothes sizes. There is no standardisation.  Take the mushrooming of American style muffins. They can fluctuate in portion size from 72g to 130g. Consequently calorific values range between 280-475 calories. Bagels have also succumbed to the super-sization trend. They’re reported to be on average 24 per cent larger compared to 20 years ago.  Unsurprisingly the British Heart Foundation has recently called for a review of food portion sizes in the UK.

The good news is that by making small tweaks to your portion sizes, you’ll rein in the calories without feeling deprived or hungry. Call it the Un-diet approach. What’s more you’ll become more alert to portion super-sizing in cafes and restaurants.

Use the following advice to help you make informed choices.  Plus the visual guide will help you become portion savvy. But do remember these are guidelines only, based on an average person’s requirements.  Dietary needs vary according to age, sex, activity level and body weight. The calorie needs of a 6 foot professional rugby player who trains for 5 hours a day, will differ from those of a person with an average build plus a sedentary job, who couch surfs after work.



Take toast. 2 thick slices of wholemeal bread have 220 calories. Bypass the medium and thick bread slices and instead opt for the thinly sliced bread ranges to halve your calories. For example with two slices of Hovis Nimble wholemeal bread you’re looking at 102 calories.


One sesame bagel has 240 calories. Add some butter and you’re looking at 315 calories (10g of butter which is about 2 teaspoons, has 75 calories).  For a calorie saving option eat one half of the bagel with a thin spread of butter (155 calories), and save the other half for the next morning. Or switch to a crumpet. A toasted crumpet with a reduced fat spread delivers 135 calories.

Try to break the sugar in your tea habit. One teaspoon is 16 calories. So if you have two teaspoons of sugar per cup, and 3 cups of tea daily, this works out at 96 calories a day. If you give up the white stuff, you could save yourself 670 calories over the space of a week.

Breakfast cereal


1 portion of breakfast cereal is recommended as 30g or three heaped tablespoons.  An average portion of a muesli type cereal clocks in at 50g. Depending on how hungry you are and your body’s energy needs, your total serving may have more than one portion.

Cereals straight out of the packet are difficult to control portion wise, unless you use scales. These are a bit of a faff in the morning. In contrast there is automatic portion control with the instant oat sachets. Take a 27g pack of original Quaker Oats. It provides 180 calories 5g fat and nearly 3g of fibre (made with 180mls of semi-skimmed milk). It’s low G.I which helps maintain an even blood-sugar level, plus the soluble fibre helps reduce cholesterol. Add some cinnamon and chopped dried apricots or banana for additional sweetness and flavour.

Another hassle free route for portion control with breakfast cereals, is to think of the size of a tennis ball. Use that as your visual cue.

The mid-morning coffee run 


A tall skim milk latte is 102 calories, versus a grande whole milk latte with 172 calories. OK we’ve altered both the portion size and type of milk here. But you get the picture about small changes reaping calorie savings. Alternatively you could switch to the occasional caffe americano.  A tall serving is 11 calories.


If you’re going to make your own lunch, it’s easy to make some calorie savings by changing the type of bread you use. A large pitta bread has 275 calories. In contrast a Warburton’s sandwich thin clocks in with 100 calories.  Go easy on the mayonnaise, as one dessertspoon delivers 90 calories. Half this amount and you’ll save 45 calories. Alternatively hold the mayo and use a thin slice of avocado (25g) instead. It provides 40 calories plus the beneficial monounsaturated fats.

When it comes to orange juice, consider eating the whole fruit. A medium orange has 59 calories and the 12 grams of fruit sugar come with 3 grams of dietary fibre which fills you up. In contrast a 330ml bottle of orange juice has 155 calories, 35g of fruit sugar and zero fibre. The recommend serving size for orange juice is about 150ml, which is half a small glass. Remember only one serving of O.J can go towards your 5 a day.

Proscuitto Baguette

If you’re buying lunch, you can cut calories by opting for Pret A Manger’s half portion of baguette. The Italian prosciutto half baguette has 284 calories. These are the smart options, as the majority of shop bought sandwiches range from 500 -550 calories.

If you’ve reached sandwich stalemate, there are lots of other portion friendly and calorie conscious options.   The Crussh zero noodles soup range include a generous amount of vegetables and despite being filling, are surprisingly calorie friendly. The ginger teriyaki chicken flavour has 212 calories. Similarly Eat offer a chicken and rice noodle soup which has 315 calories.


Start weighing your portion of lean meat, fish and chicken in order to learn the correct portion size. The recommended portion size for lean meat or chicken is 100g raw or 75g cooked. Oily fish should weigh 75g, while white fish is 150g.

Potatoes and rice are tricky when it comes to portion control. So easy to overeat and hard to gauge the right portion. But if you get savvy with portion sizing you’ll make calorie savings. For example you’ll lose a 100 calories if you exchange a large baked potato (220g) for a small one (100g). The easiest visual guide is to think of a baked potato portion as the equivalent of a computer mouse.

Likewise the recommended serving for rice is six tablespoons which is 75g. The best visual cue for rice or pasta servings is to think of the size of a tennis ball.

Once you’ve perfected your meat and potato portions, you can ensure the remainder of your plate is made of vegetables. Three heaped tablespoons of vegetables is considered one portion (80g). Keep thinking of your 5 a day fruit and veg target.


Avoid the colossal ready meals 

This is where you really need to become portion aware by taking time to read labels. Ready meals for one person should weight 210- 250g on the food label.  By pass the 400g ready meals for one.

A meat pie for one should be around 140g.

A medium sized portion of casserole or curry is considered to be 260g and shepherd’s pie is 310g.

A medium slice of pizza is 100g.


Happy hour may promote that Friday feeling, but alcohol packs a lot of calories with 7 calories per gram. This is second only after fat (9 calories per gram).  What’s more alcohol tends to bring on the munchies. Hence the calling of the midnight kebab or local chippie.


However you can still enjoy post-work drinks without derailing your efforts to curb the calories.  Opt for the light white wines such as Riesling and pinot grigio. These have less calories than the higher alcohol whites (chardonnay and sauvignon blanc) and red wines (pinot noir or syrah) .

Compared to a pina colado which has 230 calories, a 170ml glass of a light white is 140 calories.  Ask for a white wine spritzer and you’ll half the calories.  Another great choice is a gin or vodka with slimline tonic for 55 calories.


Consider down scaling to the treat size versions of chocolate and other treats. They satisfy the craving, without the excess calories, sugar and fat. For example a Cadbury Crunchie Fun Size (17g) delivers 80 calories, 3g fat and 11g of sugar. In contrast the full size bar (44g) has double the energy at 185 calories, 8g fat and a whopping 25g of sugar. Clearly the fun size delivers the sweet treat without sabotaging your daily calorie count.

Continuing the micro trend, a Tesco mini flapjack bite has 70 calories and 4g of fat.  Compare this to a full size Pret A Manger flapjack which has 280 calories and 6g of saturated fat.


A single pack of crisps should be a 25g portion and will probably deliver on average 130 calories. When it comes to the family size packs – buyer beware. They’ve increased in size, plus it’s difficult to gauge what a 25g portion looks like when you dive into a 150g family pack.  And before you know it, you’ve ended up in the I’ll- started-so-I’ll-finish moreish scenario presented by a family pack.

Yet the sobering news is, devour half a 150g pack of kettle chips, and you’re easily looking at 350 calories and 15g of fat. Best to stick to the single packs of crisps for instant portion control.

When it comes to nuts, swap the salted and roasted varieties for raw almonds. You’ll not only save on calories, but you’ll also reduce your salt and fat intake.  20 raw almonds are worth 128 calories, compared to 155 calories for a 25g serving of salted, roasted peanuts.

A visual guide: teach yourself adult portion size servings

We know using weighing scales for portion sizes is not always practical. Instead use the following visual cues to help gauge portion sizes.  


iPhone and Steak

Lean meat, chicken, fish – size of an iphone


Dairy products (yogurt and milk) – enough to fill a small tea cup (250ml) or the size of a women’s clenched fist

Cheese and Matchbox

Cheese – a matchbox size portion

Tennis Ball and Cereal

Carbohydrates (breakfast cereals, rice, pasta, noodles, grains) and serving of fruit – size of a tennis ball

Potato and Mouse

Small baked potato – size of a computer mouse

Butter Thumb

Butter, margarine, mayonnaise, sugar – size of tip of your thumb

CD and Pancake

Pancake – size of a CD

CLAIRE DONNELLY is a dietitian and has a masters degree in public health nutrition. She was the 2012 winner of the annual Caroline Walker essay in public health nutrition.  Claire is passionate about health, nutrition and well-being, and is an advocate for lifelong learning.

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