Nutrition, Nutrition

How to portion size for performance

Sometimes people assume that if something is healthy, they can have as much of it as they want, which is fine but it might not support their goals if their goal is to lose weight

So many of us assume portioning our food means eating less, but to fuel your workout and achieve your goals you may be surprised to learn that you might need to eat more not less. We asked Aquanation personal trainer Byron Manning for his tips on portion sizing to perform at your best. 

Serving size vs a portion size

To get the right amount of food to fuel your body, let’s start with the basics and clarify the difference between a serving size and a portion size.

“A serving size is a standardised amount of food,” says Manning. “It’s used to help establish recommended amounts versus a portion size which is simply the amount of a particular food you decide to have,” he explains.


Avoid these portion sizing mistakes 

According to Manning, the number one blunder gym junkies make with food is overeating. Yep, resist the urge to devour that whole jar of peanut butter friend.


“Sometimes people assume that if something is healthy, they can have as much of it as they want, which is fine but it might not support their goals if their goal is to lose weight,” warns the personal trainer.


On the flip side, Manning reckons a lot of active people underestimate how much they need to eat. “Remember, food supports the goals you want to achieve.” He adds, “depending on your goals and the type of training you might need to increase or decrease your portion size.”


Manning says it’s best to consider how much activity you’re doing and if you’re doing more you might require larger portion sizes to support performance. “Portion sizes can provide more fuel for your body to do what it needs during a workout and more fuel to recover,” explains Manning.

If you’re unsure and not seeing results, Manning recommends chatting to a sports dietitian, even if it’s just one consultation to get you on track.

Portion sizing tips

Ever looked at a serving size and thought it was a little underwhelming? We feel you.


Manning explains serving sizes are established according to the Australian Dietary Guidelines and are a standard size for everyone. So essentially, the more common you are the more applicable they are to you.


Nevertheless, Manning says these guidelines are a good starting point and suggests using scales to understand them better. “You can use scales to get an idea of how much certain quantities actually look like physically, a lot of us assume what 50g of almonds looks like but measuring it can clarify this for you,” guides the personal trainer. He reminds us that portion sizes will still vary whether you’re doing more or less activity. 


If you want to make sure whatever you’re putting on your plate ticks all the healthy boxes, Manning says “for a healthy plate, aim for half a plate of colourful veg, a quarter of wholegrain carbs and a quarter of lean protein.”

Tick. Tick. Tick.

Byron Manning is a personal trainer at Aquanation with a Bachelor of Food and Nutrition Science at Deakin University and is currently undertaking a Masters of Dietetics at Deakin University. Learn more.