Welcome back to my “FODMAP Explained” Series! This is a set of articles I have dedicated to explaining the acronym FODMAP and giving practical tips to avoid symptoms while including as wide a variety of foods as possible. In this blog post, I will explain the letter “D” in the acronym FODMAP, which stands for disaccharides (two-sugar units), and more specifically, lactose.
The“D” in FODMAP Stands for Disaccharides: Lactose
Why is lactose a FODMAP? Our body is not able to digest lactose and needs to split it into its two single sugars – glucose and galactose – using an enzyme called lactase. People who don’t produce enough lactase have trouble digesting lactose. As a result, it travels through the digestive tract unabsorbed until it reaches the large intestine where it is fermented by our bacteria. Consequently, this may cause symptoms such as excess gas, bloating, abdominal pain, and/or diarrhea.
Lactose in the low FODMAP Diet
Lactose is found in milk and other dairy products. One common misconception is that the low FODMAP diet is a lactose-free or dairy-free diet. It is not! This is a low-lactose diet, which means that you can still include a few low-lactose dairy products. Interestingly, even people who are lactose intolerant can tolerate a few grams of lactose without having symptoms. You will need to find your personal tolerance level.
Indeed, including a few dairy products while following a low FODMAP diet gives you more variety and makes it easier to get enough calcium Nonetheless, if you are a vegan or are allergic to dairy, there are many alternate sources of calcium, such as fortified non-dairy milk, legumes, some vegetables, and some nuts and seeds.

Bottom line: what can you eat?
In conclusion, during the strict elimination phase of the low FODMAP diet, you will need to avoid high-lactose products such as milk, yogurt, kefir, and ice cream. But you will be able to enjoy low-lactose or lactose-free dairy products such as:
- Aged cheeses (cheddar, Swiss, Parmesan)
- Non-aged cheeses (mozzarella, feta, paneer, queso fresco) – in small portions
- Half and half, sour cream, whipped cream – in small portions
- Lactose-free milk yogurt, kefir, cream cheese, and sour cream
- Whey protein isolate (99% lactose-free)
- Butter and ghee (these are virtually lactose-free as they are mostly a source of dairy fat)
You can find the most up-to-date list of foods in the Monash University FODMAP Diet App.
After testing their tolerance to lactose during the reintroduction phase, many people find they can tolerate lactose, or tolerate it in small portions, and can reintroduce it into their diet. If you can’t tolerate lactose, you will need to avoid it and make sure you include other calcium-rich foods. Alternatively, you can use a lactase enzyme when eating foods high in lactose.