FODMAPs are sugars and fibers that are either poorly absorbed or not absorbed at all. A low FODMAP therefore diet restricts the intake of carbohydrate-rich foods such as some grains, legumes, lactose-containing dairy, vegetables and fruits. When you add another restriction – that of a vegetarian or vegan diet, you might even wonder whether there is anything left to eat at all!
With some planning, and the help of a registered dietitian knowledgeable about FODMAPs, vegetarians and even vegans can follow a low FODMAP protocol and eat a balanced diet. As many foods are either eliminated or limited in portion sizes, vegetarians and vegans need to be especially careful in planning meals so to avoid deficiencies in protein, calcium, iron, vitamin B12 and, possibly, fiber.
Here are 3 tips to eat a balanced vegetarian or vegan low FODMAP diet.
1. Don’t skip the protein
Vegetarians are less at risk of eating too little protein as the low FODMAP diet includes eggs, lactose-free dairy products and a few types of cheeses. Vegans need to pay more attention. Each meal should include a low FODMAP source of protein such as legumes (canned lentils or chickpeas), tofu (firm, extra firm), edamame, or tempeh. I recently wrote My Guide to Eating Soy Foods on a low FODMAP Diet (including an Indonesian Tempeh recipe).
Among the low FODMAP grains, quinoa (and quinoa-based pasta), millet and oats are also high in protein - more than rice - and can contribute to the overall protein intake. According to vegetarian nutrition experts, vegetarians and vegans should aim to eat a little more protein than omnivores: about 1 g/kg body weight (instead of the general recommendation of 0.8 g/kg).
2. Include good sources of calcium
Calcium intake may be an issue for everyone on a low FODMAP diet due to the restriction of lactose. Vegetarians who like dairy products can eat lactose-free milk, yogurt, and a few kinds of hard cheeses. Vegans miss out on this food group entirely but can still meet their calcium needs by drinking calcium-fortified almond or hemp milk, and eating calcium-set tofu, and calcium-rich vegetables (bok choy and kale) and chia seeds. See more ideas in my article, 5 Tips to Eat Enough Calcium (including two tasty calcium-rich recipes).
3. Pump Up the Iron
A common pitfall for all vegetarians/vegans (whether on a low FODMAP diet or not) is eating too little iron. The best sources are, after all, red meat and organ meats. Breakfast cereals are fortified with iron but most of them are high in FODMAPs. Even so, careful meal planning can help you eat enough or close to enough. All the plant-based protein sources are high in iron (and zinc): legumes, soy products, nuts and seeds. The grains mentioned above are also rich in iron, as well as certain low FODMAP vegetables such as kale, chard, raw spinach, bok choy, and broccoli.
You may have heard that the iron from plant foods is not as well as absorbed as the one from animal foods. However, adding a vitamin C-rich fruit or vegetable (for example, kiwi, strawberries, oranges, or red bell peppers and broccoli) at the same meal greatly increases the absorption of iron. Another useful tip is to avoid drinking coffee, tea, mint tea or cocoa with meals as the flavonoids or phenolic acid in these beverages bind the iron and reduce its absorption by as much as 50-90%. Finally, it would be best to eat calcium-rich and iron-rich foods in separate meals, as calcium and iron inhibit each other’s absorption. You need not worry about the foods that contain both (such as tofu or legumes). Mostly try not to drink lactose-free milk or almond milk with your lunch or dinner, and have those very high-calcium foods with breakfast and/or snacks.
Final Food for Thought…
A paper published by Monash University earlier this year found some popular vegan foods to have either a low or negligible FODMAP content: soy cheese, coconut yogurt, pea protein isolate, kelp noodles, vegan egg replacer, nutritional yeast, agar-agar, dulse, and spirulina. Check out the Monash University FODMAP Diet App for appropriate serving sizes.
Even when doing all things right, you may still be deficient in certain of these nutrients or may simply not be eating enough. It’s best to consult with a registered dietitian trained on the low FODMAP diet to see whether you may need to tweak your meals further or need a supplement (for example, B12 for vegans). Finally, don’t forget that the low FODMAP diet is a temporary diet and, once you have completed the re-challenge phase, you may be able to include many more foods, such as more varieties of beans and lentils, perhaps soy milk, and more choices or higher portions of vegetables.