Intermittent Fasting for Beginners: Methods, Evidence...

Intermittent fasting (IF) has become one of the most talked-about approaches to eating. Unlike most diets, it focuses less on what you eat and more on when. Some people love it; others find it does not suit them at all. This guide explains the main methods, what the research shows, and how to decide whether it is right for you.

What Is Intermittent Fasting?

Intermittent fasting means cycling between periods of eating and periods of not eating. Fasting is not new: people have fasted for religious, cultural and practical reasons throughout history, including during Ramadan, Lent and Buddhist traditions.

A woman drinking a glass of water. Photo: Unsplash

Common Methods

Time-restricted eating (TRE)

You eat all meals within a set window each day. The most popular version is 16:8: a 16-hour fast (including sleep) and an 8-hour eating window, such as 10 am to 6 pm. Gentler versions include 12:12 or 14:10.

The 5:2 method

You eat normally five days a week and reduce intake to around 500 to 600 calories on two non-consecutive days.

Alternate-day fasting

You alternate between normal eating days and very low-calorie or fasting days. This is more demanding and less popular long term.

What Does the Research Show?

Weight loss: many studies show IF can help with weight loss, mainly because people eat fewer total calories. Several randomised trials, including a 2020 trial published in JAMA Internal Medicine and a 2022 trial in the New England Journal of Medicine, found that time-restricted eating produced similar results to ordinary calorie reduction, not dramatically better.
Blood sugar and insulin: some studies report improvements in insulin sensitivity, especially when the eating window is earlier in the day.
Circadian alignment: eating earlier and avoiding late-night meals may align better with the body clock.
Autophagy and longevity: animal studies on cellular "clean-up" processes are interesting, but long-term human evidence is still limited.

Overall, intermittent fasting can be a useful tool for some people, but it is not a magic solution. Food quality, total intake, sleep and activity still matter most.

Potential Benefits People Report

A simple structure with fewer decisions about snacking
Less late-night eating, which may help sleep and digestion
Greater awareness of true hunger versus habit

Possible Downsides

Hunger, irritability and low energy, especially at first
Headaches and difficulty concentrating
Overeating or poor food choices during eating windows
Social challenges around shared meals
Muscle loss if protein intake and strength training are inadequate
Possible disruption of menstrual cycles in some women with aggressive fasting

Who Should Not Fast (Without Medical Supervision)

People with a history of eating disorders
Pregnant or breastfeeding women
Children and teenagers
People with type 1 diabetes, or type 2 diabetes on insulin or sulfonylureas (risk of low blood sugar)
People taking medications that must be taken with food
People who are underweight, frail or elderly with poor appetite
Anyone with significant medical conditions

Always speak with your doctor before starting any fasting approach if you have a health condition or take medication.

How to Start Safely

Start with 12:12. Simply stop eating after dinner and have breakfast 12 hours later.
Progress slowly to 14:10 or 16:8 over several weeks if it feels good.
Prefer an earlier window, such as 8 am to 4 pm or 9 am to 5 pm, rather than late-night eating.
Stay hydrated. Water, plain sparkling water and unsweetened herbal teas such as pine needle tea are fine during the fast. Read our hydration guide.
Break the fast with a balanced meal: protein, vegetables, whole grains and healthy fats; avoid breaking it with sugar. See our blood sugar guide.
Eat enough protein and keep up strength training to protect muscle.
Listen to your body. Dizziness, extreme fatigue or obsessive thoughts about food are signs to stop.

Nutrient Quality Matters More in a Shorter Window

With fewer meals, each one matters more. Focus on nutrient-dense foods: vegetables, fruit, legumes, fish, eggs, whole grains, nuts and fermented foods. If you take supplements such as fermented cod liver oil or pine needle oil capsules, take them with food as the label directs, during your eating window.

A Sample 14:10 Day

8:00 am: water and a short walk
9:00 am: breakfast of eggs, vegetables and wholegrain toast
1:00 pm: lunch of a bean and grain bowl with kimchi
4:00 pm: snack of yoghurt and berries
6:30 pm: dinner of fish, vegetables and brown rice
7:00 pm onward: water or herbal tea only

Mindful Eating Within Any Window

Intermittent fasting works best alongside mindful eating: eating slowly, without screens, and stopping when comfortably full. See our mindful eating guide and metabolism myths.

Frequently Asked Questions

Does black coffee break a fast?

Plain black coffee and unsweetened tea contain almost no calories, and most people practising time-restricted eating include them. Adding milk, sugar or cream adds calories.

Can I exercise while fasting?

Many people walk or do light exercise in a fasted state comfortably. For intense training, eating beforehand may feel better. Listen to your body.

The Takeaway

Intermittent fasting is a flexible tool that some people find helpful for structure, weight management and avoiding late-night eating. It is not essential for health and is not right for everyone. If you try it, start gently, prioritise nutrient quality and listen to your body.

Disclaimer: This article is for general educational purposes only. These statements have not been evaluated by the Food and Drug Administration. Live Pine products are not intended to diagnose, treat, cure or prevent any disease. Always consult a qualified healthcare professional before starting a new supplement, especially if you are pregnant, nursing, taking medication or managing a health condition.