• Chloe

Do portion sizes matter?

Updated: Nov 14, 2021


Enjoy eating out again with our dietitian's advice



Do portion sizes matter?

Our registered dietitian Chloe, helps explain more.


Everyone’s an individual

Nutritional needs are totally individual as everyone is a different body size and shape, everyone does different things in their day meaning they have different energy needs. It can be useful to have a think about your activity levels while you’re at work and in your leisure time, more activity will require more energy. Even if we all ate the same thing, we would still be different shapes & sizes which is good as a reminder that what works for one person may not necessarily suit the next person. Our nutrient requirements can also vary depending on age, children have increased needs for growing, while adults don’t grow. Also as we age, we have less lean muscle mass, so older adults can require less energy. As you would expect taller people will require more energy, and people in a larger body. The nutrients we need can also depend on factors such as illness, whether we are fighting a cold or recovering from surgery nutrition can play an important role and our needs might vary temporarily.


Portion size guidance

There are many places that tell us what, when and how much we ‘should’ eat, but as mentioned above no two people are the same – so portion sizes are a guide only. This article will discuss some average or medium portion sizes that can be useful for adults, but ultimately as the expert in you you’ll be able to adjust as necessary to fit with your needs. Even individual nutrient recommendations are designed for the ‘average’ person, which technically would only suit 50% of people. It is perfectly normal to require slightly more or slightly less of a nutrient or food than others. While a guide can prove to be useful, if you are unsure of appropriate food portions, they are not an exact measurement of food or a rule. The way the food has been bought, stored, cooked and served all have an impact too so suggested portion sizes are not a target. On big days or busy days you may feel hungrier and eat more, listening to your body will help you to decide on the appropriate portion size. On quiet days you may opt for a smaller portion size, or include less snacks than busier days.


Food groups: We’ll discuss some helpful measures for different food groups that may be a useful guide.



Carbohydrate rich foods


Carbohydrate foods

A really important source of energy, so it is good to have something carbohydrate based at every meal. Pasta and rice can be difficult to judge while cooking, so try measuring the dry pasta or rice in a teacup and measure one per person.

  • One teacup of dry food per person when served as part of a meal.

  • 2 slices of bread, for example when making a sandwich.

  • Cereals can also be difficult to judge. Try about 3 handfuls of breakfast cereal.

  • A baked potato about the size of your fist.

Protein foods

Whether you’re a meat eater or not protein is an important nutrient to remember as part of your meals. Protein is key for repair and maintenance of the body cells in addition to being fundamental for growth in children.

  • Meat, fish or poultry a fillet/piece the size of a deck of playing cards.

  • 2 eggs, boiled, scrambled, poached etc.

  • 4-5 dessert spoons of beans/lentils/chickpeas etc.

  • Nuts as a snack or part of a meal one heaped tablespoon/ small handful, around 28g.

  • Tinned fish e.g tuna or sardines – 1 medium tin per person.



Colourful salad

Fruit & vegetables

A great source of vitamins & minerals, and fibre which is important for digestive health. ‘Healthy eating’ advice often states you should fill up half your plate with vegetables, but in reality, we know not every meal looks like this. Incorporating fruit and veg into meals is a great way to increase your intake and it makes a good snack too. Research has shown the more fruit and vegetables we eat per day, the more benefit we see. Remember that fresh, frozen, tinned and dried fruit and vegetables all count as a portion.

  • Fresh fruit a tennis ball size e.g. an apple, or handful of berries.

  • Dried fruit a golf ball size/ tablespoon.

  • Salad vegetables fill a small bowl to go alongside the rest of your meal.

  • Vegetables like frozen peas/frozen mixed veg 3 heaped tablespoons.



Enjoy a glass of milk with family


Dairy foods and alternatives

Also provide important nutrients like calcium and phosphorus, important for bone health & teeth. Some dairy alternatives will have a different nutritional content to cow dairy, so it is worth checking that you don’t miss out on calcium etc if choosing an alternative, many manufacturers now fortify their dairy alternatives with these nutrients so check the label for nutrients such as calcium, phosphorus, vitamin D or vitamin B12.

  • Yogurt (including plant-based alternatives & lactose free yogurt) 1 individual pot per serving, or 1/5th of a big tub, around 100g.

  • ½ pint skimmed milk, or 1/3 pint if semi skimmed milk, ¼ pint whole milk (around 150ml).

  • Cheese a piece the size of a small match box, sliced or grated will be enough to cover a slice of bread for a sandwich, or top pasta for example around 25g. Usually someone makes a joke to me here about the cheese portion size being equal to a box of safety matches, but remember to listen to your body signals and only have a larger portion of cheese if you are hungry for it! Cheese can also be quite high in salt so reducing the portion size to a small matchbox size can be a positive step to reducing salt intake. Too much salt can lead to high blood pressure and affect your heart health.

  • Soft cheeses try one dessertspoon per person, or 2 triangles of cheese.

Fats, oils & spreads

Fats are an important part of our diet and are vital to health. Essential fatty acids such as omega 3 are important for brain & joint health so it is important to ensure you include some fats in your diet. As a nutrient fat is the most energy dense (more than protein and carbohydrate which also provide energy for us) so keeping an eye on portion size can be useful to avoid consuming excess energy you don’t need.

  • Oil used in cooking one teaspoon per person, or as a drizzle on food.

  • Butter for toast or sandwiches one teaspoon, or an individual butter packet if eating out.

  • One teaspoon of mayonnaise or peanut butter per serving or one dessertspoon of salad dressing, cream or salad cream. Adding dressing and accompaniments freehand can mean a lot of extra energy provided in a meal so again is worth taking into consideration when using these types of foods.

Social Media: It is important to remember that like with many other things on social media, it isn’t always real so beautiful food images are often staged to look great and not give consideration to the appropriate portion size. Social media images are influential but not always realistic, on top of that many influencers or celebrities are not qualified to be giving nutrition advice. It is best to stick with the portion size you know is normal for you.


Chloé is a registered dietitian and is passionate about promoting a whole-person approach to health and helping clients to feel empowered. Her specialities are weight management, IBS, plant-based diets and cancer rehabilitation. Book a free 15 min call to see how Chloe can help you. Also, remember to get your free nutrition assessment to get the best nutritional advice for you.



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