Guide to bariatric portion sizes

If you’d like to watch me talk about this in video format, head here.

Getting used to your new portion sizes after surgery takes time. Not knowing if you’re eating too much or not enough is a really common feeling. In this post, I want to run you through the overall portion sizes recommended after surgery, as well as the bariatric portions sizes for each food group so you know what to expect. If you’ve already had surgery but are struggling with weight regain, use this guide to do a little self-check.

Portion sizes at each stage

The usual recommendations for the total portion size of a main meal is around 1 cup of food long term post op. However, I usually try not to encourage my clients to focus solely on cup sizes as there can be bit variation in the sizes tolerated person to person – meal size might vary between ¾ cup or 1 ½ cups for example.

I suggest you portion out a cup of food and if you don’t eat it all that’s fine! If you do eat it all and you are still hungry and you have eaten mindfully then it is also okay for you to go back and have a little more. 

If you are only new to the sleeve (within 6 months or so of surgery), your portion sizes will be less. The first couple of weeks after surgery you should be able to manage around ¼ cup of fluid per 20-30 minutes. 3-4 weeks post op when on puree this increases to around ½ cup. Then as the swelling goes down you will be able to eat a little bit more at your meals, progressing to around 1 cup of soft/solid foods a few months after surgery. 

Bariatric portion sizes for food groups 

Not only do we need to consider total portion size of meals, we also need to consider what those meals are made of. Long term after a sleeve I encourage my clients to follow the bariatric food pyramid (see below). This means ideally you’ll have fruit once a day, veggies twice a day and protein or dairy three times a day. 

A serve of fruit according to the Australian Dietary Guidelines is 150g or 1 medium piece of fruit. After a sleeve a serve of fruit will be about half of this. For example a bariatric serve of fruit would be 1 small piece of fruit such as an apricot or plum, ½ cup of berries, or ½ medium piece of fruit such as an orange, banana or apple.

A bariatric serve of vegetables after a sleeve is also about ½ cup, or half your meal. Go for any veggies you like, although you will eat less cooked veg compared to salad because salad leaves are quite airy and fluffy (1 cup of baby spinach may compress to around ½ cup for example).

A bariatric serve of protein is about half the size of your palm or ~30g of cooked meat. This is half of the usual portion of meat which is 65g cooked or 90-100g raw. To make sure you actually eat a meal that is half protein and half veg, alternate your mouthfuls of protein and veg while you eat, rather than eating all of the protein first and running out of space for the veg (or visa versa). 

A bariatric serve of dairy is again, about half that for the regular population, so 125ml milk, 100g yogurt or 20g (1 slice) of cheese. This may not seem like much which is why calcium and vitamin D supplementation is recommended daily.

Lastly, sadly there isn’t any room for discretionary foods (or extras) in the daily diet after a sleeve. If you are eating discretionary foods regularly, then you will be displacing other foods that have the nutrients you need in your day. For example if you start eating lots of biscuits, chocolate or cake then you may not have room for enough fruit, veg or protein.

The importance of ignoring portion sizes…

Now for a disclaimer… Please take all of this with a grain of salt – everyone is slightly different in terms of portions they can manage and what suits them. So, if you are still hungry after eating a 1 cup-portioned meal, go back and have some more. BUT before you do, check that you have eaten that meal mindfully:

• Have you taken 20-30mins to eat your meal?
• Did you chew your food thoroughly and slowly?
• Where do you sit on the hunger scale? Do you really want more or is it more than you actually need?

If you can learn to listen to your new stomach you’re on the right track to healthy habits long term. If you are still unsure as to what portion size is right for you, or need some advice to get back on track, catch up with your team – that’s what they’re there for!