Combining the low FODMAP diet with a vegan diet can be a challenge, as most FODMAPs (excluding lactose) are found in plant based foods. A top priority when combining the diets is getting enough low FODMAP vegan protein.
What are our protein needs & where do legumes fit?
According to registered dietitian, Virginia Messina (she’s a vegan), people on a vegan diet may need approximately 10% more protein than people on a normal diet (omnivores), this is because plant proteins are harder to digest (1). Ideally you should aim for 0.9 g of protein per kg of body weight (1). For example, if you weigh 60kg you would need approximately 54 g of protein per day. This shouldn’t be an issue if you eat a range of low FODMAP plant based foods, meet your calorie needs, and consume some legumes each day.
Don’t be tempted to cut out legumes altogether when you transition onto a low FODMAP diet. While many legumes are high FODMAP (peas, red kidney beans, black beans, soya beans just to name a few), there are some low FODMAP legume options. It’s important that you continue to consume low FODMAP legumes, as they contain higher levels of lysine and isoleucine, as well as a range other other vegan protein sources to make sure you meet all your essential amino acid requirements. It is recommended that you consume at least three serves of legumes per day (1). These serves could include: peanuts, peanut butter, canned chickpeas, canned lentils, firm tofu, soy protein milk, or tempeh.
Low FODMAP Vegan Protein Sources
Regular tofu
Regular tofu is made from curdling fresh soy milk and pressing the curds into block moulds (2). It is commonly known that soy beans are high FODMAP, so you might be wondering why regular tofu is low FODMAP. We know that FODMAPs, especially GOS and fructans are water soluble (3). During manufacturing regular tofu is pressed, which reduces the water content and drains out some of the GOS (galacto-oligosaccharides), making it low FODMAP (3). The firmer the tofu is, the less water content it has, and in theory the lower in FODMAPs it will be. Just remember to drain your regular tofu well. According to Monash University a low FODMAP serve of tofu is 170g, which according to Self Nutrition Data contains 27g of protein (4 5).
Please note that silken tofu is high FODMAP and you will need to avoid it during the low FODMAP phase of the diet.
Tempeh
Tempeh is made from cooked soy beans that have been slightly fermented (6). The fermentation of the soy beans reduces the FODMAP content down to levels within the low FODMAP threshold (7). Tempeh is firmer and more flavourful than tofu and it has a slightly nutty taste. A low FODMAP 100g serve of tempeh contains 19g of protein (5)
Soy Protein Milk
Selecting a plant based milk which is high in protein can help you sneak more protein into your diet. Soy milk made from soy protein is a good low FODMAP option, as it contains about 8g of protein per 250mls (7 8). Just be aware that some soy milks made from whole or hulled soy beans are high FODMAP, so make sure you read the labels carefully and check the Monash low FODMAP app for serving size guidelines.
Quorn Mince
Quorn mince is a meat substitute made from mycoprotein, which is derived from a member of the fungi family (9). It’s low in fat and high in protein making it a good option (9). Not all quorn products are vegan approved so check what additional ingredients and additives have been used, also make sure your quorn products do not contain onion or garlic. A low FODMAP 75g serve of quorn mince contains 12g of protein (5).
Canned lentils & chickpeas
Many pulses and legumes are high FODMAP, which can make consuming three serves of legumes a day challenging. The good news is that oligosaccharides (fructans & GOS) found in pulses and legumes are water soluble (Monash Low FODMAP App, 2016). This means that canned chickpeas and lentils are lower in FODMAPs, because the GOS leach out of the chickpeas/lentils and into the water (4). Just make sure you rinse them well before using. A low FODMAP ½ cup serve of canned lentils contains approximately 9g of protein, whereas a ¼ cup serve of canned chickpeas contains approximately 3g of protein (5).
Nuts & Seeds
Adding a handful of low FODMAP nuts and seeds into your daily diet can be a great way to boost your protein levels (7). Try starting your day with a chia seed bowl, have a handful of peanuts and pumpkin seeds as a snack, and enjoy vegetable sticks covered in peanut butter or sunflower seed butter for an protein packed afternoon pick me up. Low FODMAP nut & seed butters are an easy way to boost your protein consumption as a 2 tablespoon serve contains 6 to 7 grams of protein (5).
Grains
Often people think that grains only contain carbohydrates, however, some grains contain high levels of protein. Quinoa is a super grain and 1 cup contains 8 grams of protein (5). Oats are another good source of protein as they contain about 4.2g of protein per ½ cup (7). Try adding porridge back into your diet testing your tolerance to a ½ cup serve of rolled oats.
| Low FODMAP Food | Low FODMAP Serving Size | Protein Level in Grams |
|---|---|---|
| Tempeh | 100g | 19g |
| Regular tofu (firm) | 170g (2/3 cup) | 27g |
| Quorn Mince | 75g | 12g |
| Canned lentils | 46g (1/2 cup) | 9g |
| Canned chickpeas | 42g (1/4 cup) | 3g |
| Pumpkin seeds | 28g | 7g |
| Peanuts | 28g | 5g |
| Chia | 28g | 4g |
| Walnuts | 28g | 4g |
| Macadamia nuts | 42g | 3g |
| Sunflower seed butter | 32g (2 tbsp) | 6g |
| Peanut butter | 32g (2 tbsp) | 7g |
| Soy milk made from soy protein | 250ml (1 cup) | 8g |
| Quinoa (cooked) | 185g (1 cup) | 8g |
| Oats | 50g (1/2 cup) | 4.2g |
(Information sourced from: Monash Low FODMAP App, 2016; Self Nutrition Data, 2016; Taylor, 2014)
High FODMAP Protein Sources To Avoid
Lentil Burgers
Commercially produced lentil burgers are likely to be made from dried lentils (these are higher in FODMAPs) and can contain onion and garlic. According to Monash University lentil burgers are high FODMAP and you should avoid them during the low FODMAP phase of the diet (4).
Falafel
Commercially produced falafel is made from mashed fava beans or chickpeas and they often contain onion and garlic. Falafal is high FODMAP and this means you should avoid it during the low FODMAP phase of the diet (4).
Silken Tofu
Silken tofu is unpressed, which means, unlike regular tofu, the water and FODMAP content is not drained out of the tofu. According to Monash University silken tofu is high FODMAP for GOS (oligosaccharides) (4).
Final Thoughts
While on a vegan diet there are plenty of high protein foods that are low FODMAP which you can choose. Dietitians recommend that you aim to eat three serves of legumes (soy milk, tofu, tempeh, peanut butter, canned lentils or chickpeas) per day. Also make sure you eat a wide range of grains and vegetables to help you meet your daily protein and nutrition targets. If you are combining the vegan and low FODMAP diets, it is recommended that you consult with a FODMAP trained dietitian to make sure your diet remains nutritionally adequate.