Intermittent fasting has become an incredibly popular health and fitness trend in recent years. But what exactly is intermittent fasting, and is it right for you? This complete guide covers everything a beginner needs to know to get started with intermittent fasting.
What is Intermittent Fasting?
Intermittent fasting (IF) is an eating pattern that involves cycling between periods of fasting and eating. It doesn’t specify which foods you should eat, but rather when you should eat them.
The most common intermittent fasting methods involve:
- 16/8 method: Fast for 16 hours per day, and restrict eating to an 8-hour window. For example, skip breakfast and eat between 12–8 p.m. This is the most popular IF method.
- 5:2 diet: Eat normally 5 days per week, and fast or eat 500-600 calories on 2 non-consecutive days.
- Alternate day fasting: Fast every other day, limiting intake to 500-600 calories on fasting days.
- The Warrior Diet: Eat small amounts of raw fruits and vegetables during the day, then enjoy one huge meal at night.
- Eat-stop-eat: Fast for 24 hours, once or twice per week, allowing yourself to eat normally otherwise.
The fasting period length can vary from 12-36 hours depending on the method. The main takeaway is that you’re cycling between a period of fasting and a period of eating.
Benefits of Intermittent Fasting
Intermittent fasting has skyrocketed in popularity due to its numerous health benefits:
By limiting the window of time you’re allowed to eat, you reduce your calorie intake, leading to weight loss. Intermittent fasting enhances hormone function to facilitate weight loss as well.
Studies show alternate-day fasting over 3–12 months reduced body weight by up to 7% and decreased body fat by 3–6% (1).
Intermittent fasting impacts heart health by improving blood pressure, total and LDL cholesterol, blood triglycerides, and markers of inflammation (2).
Blood sugar control
Fasting has been shown to improve sensitivity to the blood sugar-regulating hormone insulin. Some studies show short-term intermittent fasting leads to improved blood sugar control (3).
Restricting calories via intermittent fasting may promote longevity and slow aging by enhancing cells’ ability to repair damaged DNA (4).
Intermittent fasting boosts a brain chemical called BDNF, which may protect against Alzheimer’s disease. It also improves cognitive function (5).
Animal studies suggest that intermittent fasting may prevent cancer by blocking tumor development (6).
Intermittent fasting triggers adaptive cellular stress responses that strengthen resistance to damage and disease (7).
In summary, intermittent fasting provides incredible benefits for weight loss, heart health, blood sugar control, anti-aging, brain health, cancer prevention, and longevity.
Is Intermittent Fasting Right For You?
Intermittent fasting can be a sustainable, easy way to improve health—but it’s not right for everyone.
Here are some factors to consider when deciding if intermittent fasting is a good fit:
- Medical conditions: Intermittent fasting can be dangerous for those with diabetes or issues with blood sugar regulation. Consult a doctor first.
- Pregnancy or breastfeeding: IF is not recommended while pregnant or breastfeeding.
- History of disordered eating: Fasting may trigger or promote eating disorders in some.
- Medications: Some meds must be taken with food for proper absorption. Check with your doctor.
- Caffeine sensitivity: Caffeine consumption may need to be limited during the fasting window.
- Sleep issues: Hunger from fasting can disrupt sleep. Time your fast so it ends a few hours before bed.
- Stress: Fasting may heighten stress and anxiety. Don’t use it as a coping mechanism.
- Athletic performance: Consult a sports dietitian to tailor intermittent fasting for your training needs.
Intermittent fasting is likely safe for most healthy adults. But you should always check with your healthcare provider before starting. Pay attention to your body and stop if you experience any issues.
How to Start Intermittent Fasting
If intermittent fasting sounds like a good fit, here’s a step-by-step guide on how to get started:
- Pick your method
Select one of the intermittent fasting methods that fits your lifestyle best. The 16/8 method is the simplest for beginners.
- Start gradually
Begin by fasting for 12 hours, then gradually increase the fasting period. This allows your body time to adapt.
- Listen to your body
Pay attention to hunger cues and other signals from your body. Adjust your fasting times if needed.
- Stay hydrated
Drink plenty of water, herbal tea, and other calorie-free drinks while fasting. Proper hydration is key.
- Get enough sleep
Fasting can impact sleep. Ensure adequate, quality sleep of 7–9 hours per night.
- Exercise smart
Time exercise so you have fuel in your system. Exercising in a fasted state takes some adaptation.
- Optimize meals
Focus your meals on protein, healthy fats, and complex carbs to feel satisfied.
- Supplement if needed
Some take supplements to help with energy, hunger, cravings, or workout recovery during fasting.
- Stick with it
Stay consistent and be patient. It takes some trial and error to find your optimal fasting routine.
The best approach is starting with a reasonable fasting goal, listening to your body, and slowly increasing fasting duration. Patience and consistency are key.
What to Eat While Intermittent Fasting
One huge benefit of intermittent fasting is that it doesn’t restrict what foods you eat, just when you eat them. However, nutrition still matters.
To get all the benefits of intermittent fasting, focus on eating whole, unprocessed foods during your eating window.
Here are some examples of healthy meals to eat while intermittent fasting:
Breakfast: Omelet with veggies, avocado toast, yogurt and fruit
Lunch: Salmon salad, veggie stir fry with quinoa, chicken wraps
Dinner: Grilled chicken with roasted vegetables, turkey burger with sweet potato fries
Snacks: Hardboiled eggs, fruits, nuts, seeds, protein shake
Aim for a balanced diet featuring lean proteins, healthy fats, complex carbs, and plenty of vegetables. Be sure to get enough calories, nutrients, and hydration when not fasting.
Avoid ultra-processed junk foods. The IF benefits are maximized when combined with an overall healthy diet.
Intermittent Fasting Tips and Tricks
Here are some handy tips and tricks to make intermittent fasting easier:
- Stay busy – Boredom can lead to focusing on food. Stay occupied with work, hobbies, exercise, or socializing.
- Drink coffee – Having black coffee in the morning can help curb hunger.
- Supplement – Caffeine, BCAAs, etc. can help with hunger and energy deficits from fasting.
- Brush teeth – This cues your body that the eating window is closed.
- Go to sleep – Avoid late-night snacking by heading to bed.
- Do workouts – Exercising helps burn calories and distract from hunger.
- Sparkling water – Carbonated water can help control appetite.
- Plan meals – Meal prep ensures you have healthy options when the eating window opens.
- Avoid triggers – Limit exposure to food cues when fasting by working away from the kitchen.
Be flexible and modify intermittent fasting to suit your lifestyle needs. With patience and smart strategies, intermittent fasting can be simple to stick to.
Answering Common Intermittent Fasting Questions
Let’s address some common questions people have about intermittent fasting:
What can I drink during the fast?
Unsweetened coffee, tea, water, and other zero-calorie beverages are fine. Avoid caloric drinks, juice, or milk.
Will I lose muscle?
Loss of lean mass is unlikely with intermittent fasting when combined with exercise and sufficient protein intake.
Can I exercise while fasting?
Yes, light to moderate intensity exercise can be done. Intense training may require fueling up beforehand.
Will intermittent fasting slow my metabolism?
No. Studies show intermittent fasting causes little to no metabolic slowdown (8).
What if I feel sick when fasting?
Dizziness, nausea, and headaches can happen initially. This usually resolves within a week as your body adapts.
How much weight will I lose?
Results vary but intermittent fasting can promote fat loss of 3–8% over 3–24 weeks (9).
Be sure to do your research and consult a healthcare provider to address your unique concerns about intermittent fasting. Don’t hesitate to modify or stop your fasting plan if you feel unwell.
What is intermittent fasting?
Intermittent fasting is an eating pattern that cycles between periods of fasting and eating. It focuses on when you eat, not what you eat. The most popular methods involve fasting for 16-20 hours per day or fasting completely for 1-2 days per week.
How does intermittent fasting help with weight loss?
By restricting the hours of the day when you eat, intermittent fasting reduces your overall calorie intake, which promotes weight loss. Fasting also positively influences hormone function to facilitate fat burning.
What are the benefits of intermittent fasting?
In addition to weight loss, intermittent fasting has been shown to improve heart health, blood sugar regulation, brain function, anti-aging processes, cancer prevention, and longevity.
What should I eat when intermittent fasting?
You don’t need to restrict what foods you eat, just focus on eating whole, nutritious foods like lean proteins, healthy fats, vegetables, and complex carbohydrates during your eating window. Avoid processed junk food.
Can I exercise while intermittent fasting?
Yes, light to moderate intensity exercise can be done during a fast. More intense workouts may require you to fuel up beforehand. Give your body time to adapt to exercising in a fasted state.
How long should my intermittent fasting window be when starting?
Start with a 12-14 hour fast, then gradually increase the length until you find what works best for your body and lifestyle. Most beginners start with the popular 16-hour fast followed by an 8-hour eating window.
Will intermittent fasting cause muscle loss?
Loss of muscle mass is unlikely with intermittent fasting when you combine it with exercise and consume enough protein during feeding periods. Take BCAA supplements if concerned about muscle breakdown.
What are some tips for intermittent fasting success?
Tips include staying busy during the fast, drinking coffee, exercising, meal prepping, going to bed early, drinking water and sparkling water, taking supplements, and avoiding triggers like the kitchen.
Is intermittent fasting safe?
Intermittent fasting is likely safe for most healthy adults but you should consult your doctor first, especially if you have any medical conditions or take prescription medications. Stop if you feel unwell while fasting.
The Bottom Line
Intermittent fasting involves cycling between periods of eating and fasting. It’s a simple, flexible, and sustainable approach to health shown to provide remarkable benefits.
Give intermittent fasting a try by starting gradually, listening to your body, staying hydrated, and eating nutritious foods. Be consistent and stick with it for a few weeks to see amazing results on your weight, health, and well-being.