How much should you be eating? Your guide to portion sizes

Published June 2024 | 5 min read
Expert contributors Tracy Leung, nutritionist and HCF health coach; Margaret Hays, accredited practising dietitian and spokesperson for Dietitians Australia 
Words by Beth Wallace

Learn why you may need to adapt your food serving sizes as you age to maintain a healthy weight, plus tips to measure and manage portion control. 

It’s important to eat foods that not only meet your body’s energy and nutritional needs at every age, but also that allow you to maintain a healthy weight. For senior Australians – the age group most prone to being overweight or obese – paying close attention to what and how much you eat later in life is particularly important. 

According to the National Health Survey, 75% of people aged 65 to 74 were overweight or obese in 2022, compared with roughly 42% of those aged 18 to 24. 

Weight gain is common at this older life stage for several reasons, says Tracy Leung, nutritionist and health coach at HCF. 

“As we age, we may not be as active as we were and so we need fewer kilojoules,” she says, adding that decreases in lean muscle mass from about the age of 40 likewise lower the amount of energy (kilojoules) our bodies require. 

“We may also have a reduced appetite, sometimes due to dental problems or social isolation,” continues Tracy. “Therefore, with a smaller amount of food, we need to ensure it is packed with more nutrients – such as protein, vitamins, minerals and fibre.” 

Not eating enough, or not eating the ‘right’ types of food, to meet your needs can negatively impact both short- and long-term health. One of the common short-term results is low energy levels, which can present as physical tiredness and mental fatigue or lack of concentration. In the long term, it may lead to muscle loss, nutrient deficiencies and a weakened immune system. 

On the flipside, if you regularly eat more than you need, your body takes in more energy than it can burn through physical activity, which can lead to weight gain. Data reveals being overweight (including obesity) is linked to 30 diseases, including 17 types of cancers, four cardiovascular diseases, three musculoskeletal conditions, type 2 diabetes, dementia, asthma and chronic kidney disease. 

“Additionally, being overweight or obese can impact on our mental wellbeing, including having low self-esteem, depression and anxiety,” says Tracy. 

Eating for your age 

The Australian Guide to Healthy Eating recommends people enjoy a wide variety of foods each day from the five food groups:  

• vegetables and legumes/beans 
• fruit 
• whole grains 
• lean meat and poultry, fish, eggs, tofu, nuts and seeds 
• milk, yoghurt, cheese and/or alternatives.   

The guidelines also recommend avoiding ‘discretionary choices’ that are high in kilojoules (kJ), saturated fat and added sugars and/or salt. This includes biscuits and cakes, processed meat, pies and pastries, and sugary or alcoholic drinks.  

Even when eating nutritious foods, servings should be limited, with the recommended number varying according to factors like age and gender, as well as weight, height and activity level. For example, the guidelines recommend that men aged 19 to 70 should aim to eat six serves of whole grain foods each day, then four-and-a-half serves after age 70. Meanwhile, women aged 19 to 50 are advised to eat six serves of whole grain foods a day, but this drops to four serves for those aged 51 to 70, then three serves beyond age 70. People who are taller than average or more physically active may need to consider additional serves.

With only 5% of Australian adults eating the recommended amounts of both fruit and vegetables, focusing on these two food groups is a good first step towards breaking overeating habits, says accredited practising dietitian and Dietitians Australia spokesperson, Margaret Hays. “My goal for most people I work with is to increase their non-carb vegetable intake – things like broccoli, capsicum and carrots – as well as their protein and fibre targets,” she says.

“Once people have their protein and fibre intake sorted, they're crowding out space for high-calorie foods and they feel more satisfied, so don't ‘need’ those foods as much anyway.”

If eating for weight loss, rather than weight management, you could also reduce the guidelines’ carbohydrate (whole grain) serving sizes, Margaret adds. 

How much is a standard serving size? 

You can find the recommended serving sizes for each food group in the Australian Dietary Guidelines, along with some helpful examples. For instance, a standard serve of vegetables is about 75g (100 to 350 kJ) or:  

• ½ cup cooked green or orange vegetables (for example, broccoli, spinach, carrots or pumpkin)  
• ½ cup cooked, dried or canned beans, peas or lentils 
• 1 cup green leafy or raw salad vegetables  
• ½ cup sweet corn  
• ½ medium potato or other starchy vegetable (sweet potato, taro or cassava)  
• 1 medium tomato. 

If it’s not practical to measure or weigh your food for every meal, these visual cues demonstrate what healthy serving sizes look like. 

• Fist = 1 piece of medium-size fruit or 1 cup of raw salad vegetables. 
• Rounded handful = ½ cup cooked vegetables or ½ cup cooked rice/pasta or noodles. 
• Small handful = 30g unsalted nuts. 
• Palm of your hand (excluding fingers) = 100g raw meat, poultry or cooked fish. 
• Thumb tip = 1 teaspoon oil, sugar or margarine/butter. 
• Matchbox = 40g hard cheese. 
• Computer mouse = 1 medium baked potato. 

It’s important to note that a standard serve is not necessarily the same as a portion, warns Tracy. “Portion size is the amount we actually eat,” she says.  

For example, a standard serve of bread in the Australian Dietary Guidelines is one slice.  

When we have a sandwich, she explains, the portion size of bread is two slices, which equates to two serves. Larger food portion sizes also mean more kilojoules.  

Plan and prepare

One of the best ways to make sure you’re eating foods that meet your body’s energy and nutritional needs is to plan ahead, says Margaret.

Rather than skipping breakfast in favour of a coffee, grabbing lunch that lacks protein and/or vegetables, then overcompensating with lots of food in the evening, she suggests preparing nutrient-dense meals and snacks to eat at regular intervals throughout the day.

For main meals, the plate or bowl (ideally entrée-sized, for portion control) should be broken down as follows: half for non-carb vegetables or salad, a quarter for protein and a quarter for carbohydrates.

“You need to eat foods that are filling and satisfying,” says Margaret. “Foods like legumes – chickpeas, kidney beans, lentils – will keep you full for a long time, whereas white bread, rice and pasta won’t, so are easy to overeat.

“And don’t forget there can be lots of kilojoules in drinks, such as milky coffee, juice and wine – they all add up.”

Variety is the key to keeping meals interesting, adds Tracy, who recommends eating 30 different plants each week, including herbs, spices, legumes and whole grains. She also suggests making meals more appealing by using colourful vegetables and experimenting with textures – combining cooked and raw vegetables in salads, alongside nuts, seeds and lemon zest.

“Add interesting flavours, with spices such as cinnamon and cardamom on your porridge, for example,” she adds, “and a variety of herbs and spices with your lunch and dinner.”

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