Intermittent Fasting for Beginners: 16:8, 14:10 and 5:2 Explained
By Body Reset Guides editorial team · 6 min read
Quick answer: Intermittent fasting (IF) means eating within set times and going without food, or with much less food, at others. Common styles are time-restricted eating (such as 12:12, 14:10 or 16:8) and the 5:2 approach. Research suggests IF can help some people eat less overall, with results similar to standard calorie reduction. It isn't suitable for everyone, so check with your doctor first.
Key takeaways
- IF is about when you eat. What you eat still matters.
- Gentle styles like 12:12 or 14:10 are a common starting point.
- Studies generally find IF works about as well as other ways of eating less, not better.
- Don't fast without medical advice if you have diabetes, take medication, are pregnant, are under 18 or have a history of eating disorders.
What is intermittent fasting?
Instead of focusing only on what you eat, IF sets a pattern for when you eat. It's not a single diet but a group of approaches.
What are the main types of intermittent fasting?
| Style | How it works | Who it may suit |
|---|---|---|
| 12:12 | 12-hour eating window, 12-hour overnight break (e.g., 7am–7pm) | Beginners; close to many people's natural routine |
| 14:10 | 10-hour eating window (e.g., 8am–6pm) | People who already stop snacking in the evening |
| 16:8 | 8-hour eating window (e.g., 11am–7pm) | Experienced, healthy adults who aren't hungry early |
| 5:2 | Usual eating 5 days a week, much less food on 2 non-consecutive days | People who prefer a weekly rather than daily pattern |
Longer fasts and "one meal a day" are not recommended for beginners.
Does intermittent fasting work?
Some people find a clear eating window helps them cut down on late-night snacking. However, research comparing IF with ordinary calorie reduction has generally found similar results. For example, a 12-month randomized trial published in the New England Journal of Medicine in 2022 found that adding time-restricted eating to calorie restriction did not lead to significantly more weight loss than calorie restriction alone. The British Heart Foundation also notes that the best approach is the one you can stick to.
In other words, IF is a tool, not magic. It may suit your routine, or it may not.
How do I start intermittent fasting safely?
- Check with your doctor first, especially if you have a health condition or take medication.
- Start with 12:12. Finish dinner and don't eat again until breakfast 12 hours later.
- Keep meals balanced in your eating window: vegetables, protein, whole grains and healthy fats.
- Drink water, and plain tea or coffee if you like.
- Move to 14:10 only if 12:12 feels easy after a couple of weeks.
- Stop if you feel dizzy, unwell, very irritable or preoccupied with food.
Who should not try intermittent fasting?
Speak to your doctor before trying any fasting if you:
- have type 1 or type 2 diabetes, or take insulin or other glucose-lowering medicines
- take medicines that need to be taken with food
- are pregnant, breastfeeding or trying to conceive
- are under 18, or older and frail
- have a current or past eating disorder
- are underweight or have been losing weight without trying
- have a long-term health condition
Frequently asked questions
What is intermittent fasting?
Intermittent fasting describes eating patterns that alternate eating periods with periods without food. It is about timing, not a required food list, and it is not suitable for everyone. Regular meals are also a valid approach. Discuss any proposed change with your doctor if your health or circumstances require extra caution.
Is intermittent fasting safe?
Intermittent fasting is not suitable for everyone, and a planner cannot establish whether it is safe for you. Pregnancy, breastfeeding, an eating disorder history and some health conditions or medications require particular caution. Talk with your doctor before changing meal timing; the tool is not permission to ignore medical guidance.
What is intermittent fasting 16/8?
The label 16/8 describes a daily schedule with a sixteen-hour period without food and an eight-hour eating window. It is a description, not a recommendation or a promise. Whether any change in meal timing is appropriate depends on your circumstances; ask your doctor before trying it if there are health concerns.
Is intermittent fasting safe during pregnancy?
Do not use an eating-window tool as guidance for fasting during pregnancy. Pregnancy changes nutritional needs, and meal timing should be discussed with your maternity care team. This website cannot assess your circumstances. Keep following your existing care advice rather than adopting a fasting schedule from a general calculator or article.
Is intermittent fasting safe while breastfeeding?
An online planner cannot tell you whether fasting is appropriate while breastfeeding. Your nutritional needs and circumstances deserve individualized discussion with your healthcare provider. Do not interpret a suggested schedule as medical clearance or change an established care plan because of it. Regular meals remain an option without using an eating window.
Sources
Last reviewed by the Body Reset Guides editorial team
General information only, not medical advice. Fasting is not suitable for everyone. Talk to your doctor before changing how you eat, especially if you take medication.
Information only — not medical advice. Our guides do not diagnose, treat, cure or prevent any condition. Talk to your doctor or healthcare provider before changing your diet, exercise or medication. In an emergency, call your local emergency number (911 in the US, 999 in the UK, 112 in the EU, 000 in Australia). See our medical disclaimer.