The Daniel Fast: 21 days of plants and water, for faith first. The body notices too.
A partial fast taken from the Book of Daniel, kept by many Christians. It's a spiritual practice, not a weight-loss plan. Here is what it involves and what the small amount of research has found.
The short version
- What it is
- A partial fast, usually 21 days: fruit, vegetables, whole grains, legumes, nuts, seeds and water. No animal food, sugar, refined food, caffeine or alcohol.
- Why people do it
- Prayer, devotion and spiritual focus. Health is a side effect, not the point.
- Watch out for
- Low protein if you don't plan it, and a drop in "good" HDL cholesterol in the studies.
- Evidence
- A faith practice, not a health diet. A handful of small, short studies, mostly from one lab.
- Our take
- If you keep it, we plan around it for the 21 days. Your church, not our app, decides the rules.
What the Daniel Fast actually is
The Daniel Fast takes its name from the prophet Daniel. In the first chapter of the book that bears his name, Daniel turns down the royal food and wine at the Babylonian court and asks for vegetables and water for ten days. In chapter ten, during three weeks of mourning, he eats no rich food, no meat and drinks no wine.1
From those two passages, Christian communities have built a partial fast. It's most often kept for 21 days, following chapter ten, although 10-day and 40-day versions exist too.2
The version studied by researchers allows fruit, vegetables, whole grains, legumes, nuts and seeds, with water as the main drink. It rules out animal products, refined carbohydrates, white flour, sweeteners, additives and preservatives, caffeine and alcohol.2 In food terms it's close to a strict vegan diet without the processed stuff.
Practice varies. Some churches and individuals are stricter, some allow particular foods, and some adapt the fast for health reasons. What counts as keeping the fast is a question for you, your pastor and your community, not for a nutrition website.
How it works in your body
From a purely physical point of view, three things change. First, the fast removes the sugar, white flour and processed food that make up a large part of most diets. Second, it adds a lot of fibre from vegetables, beans and whole grains. Third, people tend to eat less without counting: in the first published study, intake fell from about 2,190 to about 1,720 calories a day, although participants could eat as much of the allowed foods as they wanted.3
Without meat, eggs and dairy, saturated fat drops, which is one reason LDL ("bad") cholesterol falls. Protein drops too, and that has a price, which we come to below.5
What you eat, what you don't
This is the version used in the research. Your church's list may differ, and that list wins.
Eaten
- Vegetables of every kind
- Fruit
- Whole grains: brown rice, oats, wholegrain wheat, barley
- Legumes: lentils, beans, chickpeas
- Nuts and seeds
- Water
Not eaten
- Meat, fish, eggs, dairy
- Sugar and sweeteners of every kind
- White flour and refined grains
- Processed food with additives and preservatives
- Coffee, black tea and other caffeine
- Wine and all other alcohol
Alcohol on the Daniel Fast
Alcohol is not part of the fast. Daniel refused the king's wine, and the published guidelines exclude all alcoholic drinks for the whole period.12 There is no lighter version of that rule here, and we don't offer one.
What the research says
To be clear about the scale: the Daniel Fast has been studied in a few small trials, most of them run by one research group at the University of Memphis, with no control group eating normally. Nobody has studied what happens after the fast ends. With that in mind, here is what they found.
Cholesterol and blood pressure fell in three weeks
In the first study, 43 adults kept the fast for 21 days. Total cholesterol, LDL cholesterol and blood pressure all fell. They rated their mood and their fullness at about 8 out of 10, and said they kept to the rules almost all the time.3
Blood sugar and insulin improved too
A second study of 39 adults, including some with high blood sugar or type 2 diabetes, found lower LDL cholesterol, fasting blood sugar, insulin and blood pressure after 21 days. Average weight went from about 74 to about 71.5 kg.4
A little lean meat and milk did about as well
A third study gave 29 people either the traditional fast or a version with one daily serving of lean meat and skim milk. Both groups saw similar improvements in blood fats and inflammation.5 In other words, much of the health effect comes from dropping the processed food and sugar, not only from dropping animal food.
In church groups, too
In a Philadelphia programme, church participants and health-plan members followed a 40-day Daniel Fast with six weekly health education sessions. Weight, waist size and cholesterol went down, and people reported better well-being.6 No control group again, and the education sessions make it hard to say what did the work.
The uncomfortable truth
"The Daniel Fast is a detox diet." That's how some marketing sells it, and it misses the point twice. Your liver and kidneys handle "detox" every day; no food plan does it for them. And the fast was never meant as a slimming plan. The studies found real changes in blood fats and blood pressure, but in small groups, over three weeks, without anyone checking what happened next.
If someone sells you a Daniel Fast shake, cleanse or supplement pack, that's a product, not part of the practice.
The risks
- Less protein, less muscle. Removing animal food cuts protein. The researchers themselves note this can cost lean body mass, which is why they tested a version with some lean meat and milk.5 Eat legumes at every meal and add nuts and seeds.
- "Good" cholesterol drops. HDL cholesterol fell along with LDL in the first study.3 Over 21 days that's not a disaster, but it's worth knowing if your HDL is already low.
- Caffeine withdrawal. Stopping coffee and tea overnight brings headaches in about half of people, plus tiredness and poor focus, usually starting within a day and lasting two to nine days.8 Cutting down gradually in the week before helps.
- Medication. In the studies, blood pressure, blood sugar and insulin fell within three weeks.4 If you take medicine for diabetes or blood pressure, talk to your doctor before you start, not after.
- Wind and bloating. Going from little fibre to lots of beans and whole grains in one day is noisy. Soak and rinse beans, and build up if you can.
Allergies: watch the staples
With meat, fish, eggs and dairy off the table, nuts, seeds, soy and grains carry more weight. If you're allergic, swap rather than drop, so protein doesn't fall even further.
| Daniel Fast staple | Allergen (EU list of 14)7 | Swap |
|---|---|---|
| Almonds, walnuts, cashews | Tree nuts | Pumpkin and sunflower seeds |
| Peanuts, peanut butter | Peanuts | Sunflower seed butter |
| Sesame seeds, tahini | Sesame | Pumpkin seeds |
| Soybeans, edamame, tofu | Soy | Lentils, chickpeas, other beans |
| Wholegrain wheat, barley, oats | Cereals containing gluten | Brown rice, quinoa, buckwheat, millet |
| Celery in soups and stews | Celery | Fennel, carrot, onion |
Don't do the Daniel Fast without your doctor if you…
- are pregnant or breastfeeding
- take insulin or other diabetes medication, including SGLT2 drugs
- have kidney disease
- are underweight or have ever had an eating disorder
- are under 18
Healthen me asks about all of these and gives you a different plan if any apply. If you have a health condition, ask your church how the fast can be adapted for you.
How we use the Daniel Fast in your plan
It's an optional 21-day module. Switch it on, and for those three weeks your plan only uses foods on the Daniel Fast list: no meat, fish, eggs, dairy, sugar, refined grains, caffeine or alcohol.
Our usual first meal after the fast is keto-friendly and often built on eggs or fish. During the module we rebuild it from plants: beans, lentils, nuts, seeds and vegetables, with protein at every meal so you don't lose muscle. Outside your daily eating window you drink water only, which fits the practice. During the 21 days there is no Rebel Day and no extra fasting day: the Daniel Fast is the fast.
What we don't do: decide what counts as keeping the fast. If your church has its own list, or you want to know whether a particular food is allowed, that's for you and your community. When the 21 days end, your normal plan comes back. If you want a structured reset without the faith side, look at Whole30. For Lent, Ramadan and Orthodox fasting calendars, see religious fasting.
This article is general information, not medical advice. If you have a medical condition or take medication, talk to your doctor before changing how you eat.
Sources
- The Bible, Daniel 1:8–16 and 10:2–3 (New International Version). biblegateway.com: Daniel 1:8–16; 10:2–3
- Trepanowski JF, Bloomer RJ. The impact of religious fasting on human health. Nutrition Journal 2010;9:57. doi.org/10.1186/1475-2891-9-57
- Bloomer RJ, Kabir MM, Canale RE, Trepanowski JF, Marshall KE, Farney TM, Hammond KG. Effect of a 21 day Daniel Fast on metabolic and cardiovascular disease risk factors in men and women. Lipids in Health and Disease 2010;9:94. doi.org/10.1186/1476-511X-9-94
- Trepanowski JF, Kabir MM, Alleman RJ, Bloomer RJ. A 21-day Daniel fast with or without krill oil supplementation improves anthropometric parameters and the cardiometabolic profile in men and women. Nutrition & Metabolism 2012;9:82. doi.org/10.1186/1743-7075-9-82
- Alleman RJ Jr, Harvey IC, Farney TM, Bloomer RJ. Both a traditional and modified Daniel Fast improve the cardio-metabolic profile in men and women. Lipids in Health and Disease 2013;12:114. doi.org/10.1186/1476-511X-12-114
- Vaughn NA et al. A 40-day journey to better health: utilizing the DanielFast to improve health outcomes in urban church-based settings. Healthcare (Basel) 2018;6(1):25. doi.org/10.3390/healthcare6010025
- Regulation (EU) No 1169/2011 on food information to consumers, Annex II (the 14 allergens). eur-lex.europa.eu/eli/reg/2011/1169/oj
- Juliano LM, Griffiths RR. A critical review of caffeine withdrawal: empirical validation of symptoms and signs, incidence, severity, and associated features. Psychopharmacology 2004;176(1):1–29. doi.org/10.1007/s00213-004-2000-x