Tofu.  To many, all tofu looks the same.  Seen one tofu, seen them all.  But there are important differences, especially if you need extra calcium or have gut issues.


What is it?

3 ingredients are used to make Tofu

  • soy
  • water
  • coagulant (remember this for later)

Fresh soy milk is curdled (with help from the coagulant) and then pressed into the familiar solid-tofu-block.


What are the different types?

You can make or buy extra firm and silken tofu.  Silken tofu has the highest water content making it great for creamy sauces, desserts, shakes and salad dressings

Firm tofu on the other hand, has most of its water removed in the pressing process.  As a result, firm tofu holds its shape better than silken tofu, making it easier to chop, slice and pan-fry.


Can I get a good dose of calcium from Tofu?

The answer is YES….and NO.

………..if you eat tofu made with a calcium-based coagulant / firming agent (usually calcium sulphate or calcium chloride)



………..if you eat tofu made with a non-calcium-based coagulant /firming agent (such as magnesium chloride or magnesium sulphate)


Look at these comparisons:

How much calcium?
Tofu, firm (made with calcium coagulant), 150g 250 – 400 mg
Tofu, firm (made with magnesium coagulant), 150g 115 – 170 mg
Calcium fortified soy, oat or rice milk, 1 cup / 250 ml 240 – 400 mg
Cows milk, 1 cup / 250 ml 260 mg


You can see that 150g tofu (made with calcium coagulant) has the same amount of calcium as 1 cup of fortified soy milk or cow’s milk.  This is equal to about a ¼ of what is recommended each day.

You can work out which coagulant / firming agent is added to tofu and whether it is a good source of calcium by looking at the ingredients list:






The first tofu, which uses a calcium sulphate coagulant / firming agent, will have a much more calcium content that the second tofu which uses a magnesium chloride coagulant / firming agent.



Is tofu ok to eat when following the low FODMAP diet?

The answer is YES….and NO.

………..if you choose firm tofu


………..if you choose silken tofu*


*Silken tofu is high in the FODMAPs GOS and fructans (oligos) so if oligos are not are problem for you, then silken tofu should not cause any gut symptoms.  Oligos come from the whole soy beans which tofu is made from.


The table below from Monash FODMAP compares the FODMAP contents of different types of tofu.

Tofu Serve size FODMAP rating
Tofu, firm, drained 2/3 cup or 160g Low in all FODMAPs
Tofu, silken 1/3 cup or 75g  

High in FODMAP oligos -GOS & fructans


Monash FODMAP think that the difference in FODMAP / oligo content is due to the way different types of tofu are made. In both methods, the oligos within the soy beans leak out into the water that the tofu is made with.  The difference is that with firm tofu, most of this ‘oligo-water’ is pressed out during processing– see you later oligos!


In summary, its all good news.  If you are relying on tofu for calcium or want to include it when on a low FODMAP diet (or both), you can!  You just need to make sure that you choose the right one.


Check out some of these delicious tofu recipes:

Marinated tofu with Asian greens & rice *

Scrambled tofu*

Tofu & spinach cannelloni

Tofu, greens & cashew stir fry

*also low FODMAP


Michelle Holt

Accredited Practising Dietitian