Orthodox fasting and diet. How to get enough protein without meat and dairy

Fasting in the Orthodox Church can reach 180 to 200 days a year. For people who watch their weight or exercise, a key question is how to get enough protein without meat, fish, dairy and eggs. It can be done, as long as you plan for it.

What you can eat and when

The fasting rules vary from place to place and from person to person, and everyone follows the guidance of their spiritual father. The Greek National Dietary Guidelines summarise the tradition as follows:

The guidelines state that prawns, squid, cuttlefish, octopus, lobster, crab and snails are allowed on all fasting days. Many of our recipes tagged ‘Fasting-friendly’ contain olive oil, so they suit the days when oil is allowed. For the days without oil, check the ingredients.

What Greek studies found

In Crete, researchers followed 120 adults for one year: 60 who fasted in all the fasting periods and 60 who did not.

• At the end of the fasting periods, those who fasted had 12.5% lower total cholesterol, 15.9% lower LDL and 1.5% lower body mass index than the others.
• They ate less fat and fewer calories, but also less protein and less calcium. Fibre and folate went up.

In another, smaller study of 59 people, those who fasted strictly for the 40 days before Christmas did not have iron deficiency. In 10 monks in Crete, the calcium they got from food was lower in the fasting week.

The studies were small and the people chose for themselves whether to fast, so the findings are of low certainty.

Other studies show what needs attention. Severe vitamin D deficiency was found in monks on Mount Athos. In 200 people who had fasted for decades, intake of vitamin B12, vitamin D, calcium and zinc was lower than in 200 people who did not fast, although most blood tests did not differ. These findings are also of low certainty.

How much protein fasting foods provide

With values from the app’s database, per usual serving:

With the servings in our database, octopus and squid give more protein than a serving of grilled chicken, and prawns slightly less, all with few calories. Pulses give less per serving, but they also bring a lot of fibre. The Dietary Guidelines suggest combining them with cereals, such as bread, rice or pasta, for better protein quality.

Three fasting days from our recipes

We made three examples using only meals from the app, without meat, fish, dairy and eggs. All three contain olive oil.

The first day has wholemeal bread with peanut butter and banana for breakfast, carrot and cucumber with hummus and nuts as a snack, fakes (lentil soup) with bread without the feta for lunch, fava (yellow split pea purée) with onion for dinner and a warm soya drink before bed. The seafood day changes lunch to octopus with short pasta and dinner to salad with black-eyed beans.

These are examples, not a plan. In the app, the grams come from your own calories. For an adult who does not exercise, the app aims for about 1.2 g of protein per kilo. So 68 g covers a person of about 57 kg and 91 g a person of about 76 kg. Read more in the article on protein.

Calcium and vitamin B12

Calcium. An adult needs about 950 to 1,000 mg a day, according to EFSA. The Dietary Guidelines list as sources pulses, almonds, okra, endive and, on days when fish is eaten, small fish eaten with their bones, such as sardines, anchovies and picarel. In our database, calcium-fortified soya drink, tahini and sesame also have a fair amount of calcium.

Vitamin B12. It is found almost only in animal foods. A serving of octopus or squid easily covers the 4 µg a day, and a serving of prawns more than half. On strict days without seafood there is almost no source of B12 among the foods in our database. Some soya drinks are fortified with B12, and this is stated on the label. The body has stores, and we don’t know whether short fasting periods cause deficiency. If you fast strictly for long periods, ask your doctor or pharmacist whether you need a supplement.

Fasting and weight loss

In the Crete study, those who fasted ate fewer calories and their body mass index fell slightly. This does not mean that fasting makes you lose weight on its own. Fasting foods have calories too, and oil, bread and nuts quickly push the total up.

In MesogeaFit you can select ‘I’m fasting today’ and choose without oil, with oil or with fish. Your calories and protein target stay the same.

Who should ask their doctor first

• Pregnant and breastfeeding women.
• People taking insulin, sulphonylureas or SGLT2 inhibitors for diabetes.
• Older people, and people with osteoporosis or low vitamin D.
• People with iron-deficiency anaemia. The Dietary Guidelines suggest eating pulses together with foods that contain vitamin C, such as tomato, pepper or lemon.
• People who have or have had an eating disorder.