What’s the right portion size for you? (2024)

Please note: The following article contains content on reducing portion sizes which may be triggering.

When it comes to putting food on our plates, it seems the average portion size in the UK has grown over the years. Most people have a rough idea of what an appropriate portion size is for them, but this is highly influenced by other factors, including the portions that they're offered.

People's tendency to eat more when portion sizes increase has been defined as a “portion size effect,” and has been the focus of many scientific studies.

“A major concern about people eating larger portion sizes than they need is they can develop learned patterns of eating behaviours that are unhealthy. Particularly if those portions relate to foods that are regarded as unhealthy,” explains Dr. James Stubbs, professor of appetite and energy balance, University of Leeds.

The reasons for this portion size effect aren't well understood. People might encounter bigger portion sizes because of "super-sized" marketing promotions, a reliance on pre-packaged food, restaurants offering larger value-for-money meals, generous written recipes or even bigger plates.

“The average size of a dinner plate has increased from 22cm in the 1970's to now being 28cm - which inevitably means portion sizes have increased. Also, restaurants almost always serve portions larger than they should be and people then find it confusing not to replicate this at home,” says dietitian and BDA spokesperson, Clare Thornton-Wood.

What is a ‘normal’ portion of food?

Spoiler! There is no ‘normal’. The size of a portion depends on several factors, including:

• Age
• Gender
• Height and/or weight
• Activity levels

“It also depends overall on what you eat over the period of a day and how often you are eating the portions,” explains Thornton-Wood.

“However, a simple and visual way of understanding portion size is to use your hands:”

• Meat – the size of your palm
• Poultry/fish - the size of your hand
• Vegetables – a cupped handful
• Carbohydrates (potato, rice, pasta etc) – a handful
• Fruit – a handful

The BDA has a comprehensive portion size guide that breaks down the main food groups and gives a description of what each suggested portion size looks like.

Stubbs explains: “Recommended portion sizes for healthy adults are generally based on a daily calorie need of 2,000 kcal per day for women and 2,500kcal per day for men.

“People vary a lot and so average values can sometimes be misleading as everyone is different and has different needs. However, there is a concern that if people consume larger portion sizes [than required] this will lead to energy intakes which are more than a person’s energy requirements.”

Easy ways to avoid portion distortion

Personalise portions: “There’s a lack of understanding that not everyone needs the same portion,” says Thornton-Wood. For example, if you’re plating up food for a family, everyone’s portion sizes should be tailored to the individual.

Use measuring spoons and scoops: “Carbohydrates such as rice and pasta are often too large. But weighing things out is time consuming,” says Thornton-Wood. “One solution is to get a scoop, which are easily available in shops or often given away by organisations trying to prevent food waste. You could even make your own measure by adding markings to a plastic cup.

“Measuring oil with a spoon is useful as portions are often over generous.”

Check the recommended portion size: How often do you check how many people that carton of soup is recommended to serve? Or how much cereal is considered a ‘portion’?

Traffic light nutritional information on the package is shown per serving size, which may be smaller than you think. If the serving size is half a packet, but the reality is that you are going to eat (or drink) the full contents, the doubled calories, fat, salt and sugar might be more than you need.

“I think the traffic light system is a useful guide if you use it to try to limit your intake of foods that are in the red zone and aim for mainly green but with some amber,” says Thornton-Wood.

“However, I do think manufacturers using more realistic portion sizes (or legislation around this) would be useful. Breakfast cereal portions are based on weight, yet the visual effect is often very small. I don't know anyone that keeps to the portion size. Realistic sizing is needed.”

“I think it can be confusing for consumers when nutritional information is given per ‘typical portion’ because many consumers, do not eat a typical portion,” adds Stubbs.

“I think it’s much more informative to tell people what is in the food they are going to eat and also what is in the food per hundred grams so that we have a standard comparison with other foods.”

Getting the balance right

Eating well isn’t just about how much food you put on your plate, though. The type of food can make a big difference to whether you feel satisfied after eating or not.

“Foods that are high in protein or fibre tend to keep you fuller for longer,” says Thornton-Wood.

“Also, foods containing a lot of water. A good example is a soup with pulses and vegetables - this provides protein (pulses), fibre (vegetables, pulses) and water (stock).

“Although fat is an energy-dense food and has the highest kcal/kg of all the macronutrients (protein, carbohydrates, fat) it does increase satiety and therefore reduces appetite. Adding a little fat to meals in the form of unsaturated fats such as olive or rapeseed oil, avocado, oily fish (salmon, trout, sardines) and nuts and seeds is useful.”

Avoiding an excess of ultra-processed foods is also important says Stubbs. “Some highly-processed foods have little in the way of nutrients but are dense in energy – with fats, sugars and/or salt and additives, some of which may stimulate energy intake and make you want to eat more.”

However, this doesn’t mean you should completely cut out your favourite ‘treats’ says Stubbs. “Food is a source of pleasure, comfort and reward and we shouldn’t completely deny ourselves of them. But if we focus on 80% healthy, lower energy-dense (larger portion) nutritious foods we still have room for 20% of our diet, as foods that add pleasure and can be more energy dense, without overconsuming them.”

But, say both experts, don’t become too hung up on portion size.

“It’s all about balance,” finishes Thornton-Wood. “We have issues in the UK with overeating and the impact that has on our waistline, and we also have people living with an eating disorder.

“People with eating disorders such as anorexia nervosa are often very rigid in their thinking about portion sizes and part of treatment often works with the fear that they associate with portion sizes, particularly when they are not considered well enough to serve themselves.”

So, it’s more important to make sure you’re having nutritious meals and snacks which contribute to good health. “Aim for a variety of foods and colours,” ends Thornton-Wood.

If you have been affected by disordered eating help and support is available.

Originally published March 2024