Intermittent fasting guides

How to Do Intermittent Fasting: A Gentle First Week

How to do intermittent fasting: pick a gentle schedule, set your eating window and check in after a week. What trials found and who should ask first.

4 min read

How Do You Read Intermittent Fasting Research?

Read intermittent fasting research with four checks: who took part, the comparison, the size of the difference and how long it lasted. What it shows.

5 min read

Intermittent Fasting Rules: The Simple Basics to Follow

The basic intermittent fasting rules: pick a schedule you can keep, no calories during the fast, eat enough, stay hydrated and stop if you feel unwell.

4 min read

Fasting Timeline: What Happens and Why Timing Varies

This fasting timeline explains how the body moves from meal glucose to liver glycogen, then to fat and ketones, and why the timing varies.

5 min read

Types of Intermittent Fasting and How They Differ

The main types of intermittent fasting: daily eating windows like 16:8, alternate-day fasting and 5:2. How each one works and what trials found.

4 min read

What is intermittent fasting? How it works

Intermittent fasting means eating in planned windows and going without calories in between. How it works, the main types and what trials found.

5 min read

Schedules and protocols

12:12 Intermittent Fasting: How It Works

12:12 intermittent fasting pairs a 12-hour eating window with a 12-hour fast. See a sample day, what trials found and who should ask a clinician first.

5 min read

14:10 Intermittent Fasting: How It Works

14:10 intermittent fasting pairs a 14-hour fast with a 10-hour eating window. See a sample day, what trials found and how to pick your window.

5 min read

16/8 Fasting: How It Works and How to Start

16/8 fasting (also written 16:8) means about 16 hours of fasting and an 8-hour eating window. See a sample day, how to build up to it and what trials found.

4 min read

18:6 Intermittent Fasting: How It Works

18:6 intermittent fasting means about 18 hours of fasting and a 6-hour eating window. See a sample day, what trials found and whether to go longer.

5 min read

20:4 Intermittent Fasting: How It Works

20:4 intermittent fasting means about 20 hours of fasting and a 4-hour eating window. See a sample day, what trials found and when a gentler schedule wins.

5 min read

5:2 Fasting: How It Works, With a Sample Week

5:2 fasting means five usual eating days and two fasting days a week. See a sample week, what trials found and who should ask first.

4 min read

Schedules and protocolsSupported evidence

Alternate Day Fasting: How It Works and What Trials Found

Alternate day fasting alternates fasting and eating days; it lost slightly more weight than other diets only in shorter trials. See who should ask first.

4 min read

Early Intermittent Fasting: Does an Earlier Window Help?

An earlier window improved 24-hour glucose in a small trial. Early intermittent fasting has no one schedule for everyone, so keep a window you can hold.

4 min read

Fasting-Mimicking Diet: What a 3-Month Trial Found

The fasting-mimicking diet means 5 low-calorie days a month. A 3-month trial with commercial ties found lower weight and blood pressure. Its limits and who should avoid it.

4 min read

Intermittent Fasting Schedule: Common Options Compared

Compare intermittent fasting schedules: 12:12, 14:10, 16:8, 18:6, 20:4 and 5:2. Trials found similar average effects, so pick one you can keep.

5 min read

OMAD (One Meal a Day): How It Works and What We Know

OMAD means eating one meal a day, with a fast of 20 hours or more. What a small trial found on hunger, blood pressure, cholesterol and blood sugar, and who should avoid it.

4 min read

During a fast

Can You Drink Apple Cider Vinegar While Fasting?

Apple cider vinegar is a grey area on a strict fast: no fasting trial tested it. What a review found on blood sugar and weight, and who should ask a clinician first.

5 min read

During a fastEarly evidence

Does Bone Broth Break a Fast? On a Strict Fast, Yes

Bone broth breaks a strict zero-calorie fast because its protein and fat add energy. See how chicken broth compares and what a modified fast allows.

4 min read

How Many Calories Break a Fast? It Depends

How many calories break a fast depends on the protocol: none in a strict eating window, and 400–800 kcal on fast days in one alternate-day trial.

4 min read

Can You Chew Gum While Fasting? Sugar-Free Gum Explained

Gum with sugar ends a strict fast. Sugar-free gum is a grey area that fasting trials never tested. What's in it and who should check the label before they chew.

5 min read

Dirty Fasting vs Clean Fasting: What's the Difference?

Dirty fasting adds milk or broth; clean fasting means energy-free drinks. See what trials tested and why they set no calorie cutoff for a strict fast.

4 min read

Can You Drink Coffee While Fasting?

Yes, if it's black: a 12-month trial allowed black coffee while fasting. See which additions end a fast, how much caffeine is too much and when to stop.

6 min read

Can You Drink Diet Soda While Fasting?

Yes: diet soda has little or no energy, and a 12-month trial allowed up to two a day. See what sweeteners, caffeine and acidity add while fasting.

5 min read

Fasting Before Blood Work: Water, Coffee and How Long

Fasting before blood work isn't always needed. When it is, follow the lab: what counts as fasting, whether water and coffee are OK, and what to ask if you take medicines.

4 min read

During a fastEarly evidence

Does Milk or Creamer in Coffee Break a Fast?

Yes, on a strict fast: milk, cream and creamers all add energy to coffee. See your options if you want to keep a coffee ritual during a fast.

5 min read

Does Stevia Break a Fast? Sweeteners While Fasting

Stevia and sucralose add little or no energy, yet no trial cited here tested them during a fast. See what the trials allowed and what WHO and NHS advise.

4 min read

Taking Medication During Intermittent Fasting

Taking medication during intermittent fasting: water is allowed, but food instructions vary by medicine. Ask before changing a dose or its timing.

5 min read

Can You Drink Tea While Fasting? Green, Black and Herbal

Yes: plain black, green and herbal tea add essentially no energy while fasting. See which additions end the fast and how much caffeine tea adds.

5 min read

Vitamins and Supplements While Fasting: Do They Break It?

Taking vitamins and supplements while fasting: sugary gummies and protein powders end a strict fast, plain tablets are a grey area. Magnesium, creatine and medicines.

5 min read

Can You Drink Water (and Lemon Water) While Fasting?

Plain and sparkling water never break a fast, and a long fasting trial encouraged it. See where lemon, juice and coconut water fit and how much to drink.

5 min read

What Breaks a Fast? Drinks, Gum and Medicines

What breaks a fast? Trials allowed water, black coffee and tea, but no calories. Gum is untested; never change a medicine to keep fasting.

6 min read

What Can You Drink While Fasting?

Water, black coffee and plain tea fit a zero-calorie fast; diet soda adds little or no energy. See what you can drink while fasting and what ends a fast.

6 min read

Food and daily habits

What to Eat After You Break a Fast

Here is how to break a fast: an ordinary meal of protein, vegetables and whole grains, eaten slowly. The window is not a licence to make up missed food.

5 min read

How to Curb Hunger During Intermittent Fasting

Hunger during intermittent fasting is expected, and trials do not show that fasting reduces it more than eating less. A gentler window may help.

5 min read

Electrolytes and Dehydration During Intermittent Fasting

Do you need electrolytes during intermittent fasting? Not for an ordinary fast, per official sources. Learn the dehydration signs to watch and when to end a fast.

5 min read

Does Intermittent Fasting Affect Sleep?

Studies of intermittent fasting and sleep find small or no effects in controlled trials. How meal timing, caffeine and habits still shape your night.

5 min read

Missed a Fast or Ended Early? What Now

Missed a fast or ended early? Record what happened and resume your usual schedule. See why you need not make up hours and how Blimbi saves partial fasts.

4 min read

What to Eat During Intermittent Fasting

What to eat during intermittent fasting is ordinary food: vegetables, fruit, whole grains, pulses and protein, with fewer sugary drinks. Amounts count.

5 min read

Goals and exercise

Does Intermittent Fasting Reduce Belly Fat? What Reviews Show

Does intermittent fasting reduce belly fat? No review shows it beats calorie-matched diets for belly fat; trials do show lower body weight.

4 min read

Goals and exerciseSupported evidence

Does Intermittent Fasting Cause Muscle Loss?

Intermittent fasting isn't proven to cause or prevent muscle loss. What trials found on lean mass, why strength training matters and who should get advice first.

4 min read

Intermittent Fasting vs Calorie Deficit: Is One Better?

Most intermittent-fasting schedules and a daily calorie deficit give similar weight loss in adults, with small, inconsistent cardiometabolic effects.

4 min read

Goals and exerciseSupported evidence

Fasting but Not Losing Weight? What Trials Say About the Plateau

Not losing weight while fasting? Trials have not studied plateaus directly; longer trials show modest loss, and none shows that switching restarts it.

4 min read

Intermittent Fasting for Weight Loss: Realistic Results

Intermittent fasting for weight loss shows modest average losses, about 4.6 kg more than control over 12 months, similar to daily calorie restriction.

4 min read

Goals and exerciseEarly evidence

Intermittent Fasting and Keto Diet: Can You Combine Them?

Can you combine intermittent fasting and a keto diet? What one 3-month trial found, why the mix is untested, and who should ask a clinician first.

4 min read

Does Intermittent Fasting Cause Starvation Mode?

Starvation mode is mostly a myth: a short eating window didn't slow energy use in a small trial, but the body does adapt after weight loss. What's real and when to worry.

5 min read

Can You Work Out While Fasting?

Working out while fasting gave strength and muscle results similar to fed training in small trials, but the studies are limited and safety comes first.

5 min read

Safety and special situations

Dry Fasting: What It Is and Why It Isn't Safe

Dry fasting means no food and no fluids, not even water. Why the dehydration risk makes it unsafe, the warning signs to know and what fasting trials allowed instead.

4 min read

Intermittent Fasting With Diabetes: Is It Safe?

Intermittent fasting with diabetes: plan with a clinician. Learn which medicines raise low blood sugar or dehydration risk during a fast.

4 min read

Intermittent Fasting for Women: What the Evidence Shows

Intermittent fasting for women: what small trials found on weight before and after menopause, what's known about hormones and periods, and who shouldn't fast.

5 min read

Safety and special situationsEarly evidence

Diabetes Medicines and Intermittent Fasting: Risks

Diabetes medicines and intermittent fasting: which ones can lower blood sugar or raise dehydration risk, and why dose changes need your care team.

5 min read

Intermittent Fasting for Older Adults: Is It Safe?

Intermittent fasting for older adults: the US NIA says there is not enough evidence to recommend fasting diets. What to ask your clinician first.

4 min read

Intermittent Fasting Side Effects: When to Stop

Intermittent fasting side effects may start with hunger, headache, dizziness or irritability. With diabetes, know the warning signs and when to seek care.

5 min read

Water Fasting: What Trials Found and Who Should Avoid It

Water fasting means only water, often for days. What small trials of 5- to 20-day fasts found, the lean mass loss two of them measured, and who shouldn't try it.

5 min read

Fasting scienceEarly evidence

Who Should Not Do Intermittent Fasting Without Advice?

Who should not do intermittent fasting without advice? Diabetes medicines, pregnancy and eating disorders need care; few data on children or over-60s.

5 min read

Fasting science

Autophagy Fasting: What the Human Evidence Shows

Autophagy fasting is often said to start at a set hour, but human evidence is thin. What the only trial measured and why no hour is proven.

5 min read

Does Fasting Lower Blood Pressure and Cholesterol?

Pooled fasting trials found small drops in blood pressure and triglycerides with time-restricted eating, but eating windows under 8 hours raised LDL cholesterol.

4 min read

Circadian Rhythm Fasting: What the Timing Trials Found

Circadian rhythm fasting: eating earlier may modestly improve fasting insulin, glucose and weight, but trials are short and vary.

4 min read

Does Intermittent Fasting Affect Insulin?

Small trials and a 2025 network meta-analysis show fasting changes glucose and insulin only a little, mostly in short studies.

4 min read

Intermittent Fasting and Ketosis: When It Starts

Reviews describe fasting ketones rising 8–12 hours in and a shift to fat and ketones 12–36 hours after the last meal: ranges, not rules for ketosis.

5 min read