If you’re considering trying the 18/6 intermittent fasting method, it’s important to understand the potential benefits and challenges that come along with it. In this article, we will dive into the details of this fasting protocol, including how it works, its potential benefits, and how to get started. Whether you’re looking to shed a few pounds or simply improve your overall health, the 18/6 intermittent fasting method may be worth considering.
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What is 18/6 intermittent fasting?
18/6 intermittent fasting, also known as the 18/6 diet or the Leangans diet, is a type of time-restricted fasting. It involves fasting for 18 consecutive hours each day and eating all meals within a condensed 6-hour window.
For example, one may finish dinner by 8 p.m. and then fast overnight until 12 p.m. the next day. The 6-hour eating window would be from 12 pm to 6 pm each day. During the 18-hour fasting period, only zero-calorie beverages such as water, unsweetened tea, and black coffee are allowed. No other foods or calorie-containing beverages can be consumed.
This daily 18-hour fast combined with a 6-hour feeding window creates a large calorie deficit that can lead to weight loss over time. The prolonged fasting period also triggers unique metabolic adaptations that enhance fat burning and provide other health benefits.
Benefits of 18/6 intermittent fasting
Many studies suggest potential weight loss and health advantages to following an 18/6 style intermittent fasting eating pattern.
Weight loss
By restricting all calorie intake to a 6-hour window, 18/6 intermittent fasting creates an automatic calorie deficit which promotes fat-burning and weight loss.
In a recent 8-week study, people practicing 18/6 intermittent fasting lost an average of 7 pounds without intentionally changing what or how much they ate in their 6-hour window. Other studies show intermittent fasting leads to comparable weight loss as traditional calorie-restricted diets over 3-12 months.
18/6 fasting is thought to aid weight loss in several ways:
- Eliminates nighttime and between-meal snacking
- Reduces overall calorie intake
- Allows the body to more consistently burn stored fat for energy by prolonging fasting periods
- It may help reduce appetite hormones like ghrelin
- Enhances hormone sensitivity that regulates fat metabolism
For weight loss, 18/6 intermittent fasting is likely most effective when combined with an overall healthy diet and active lifestyle.
Metabolic health
Beyond just weight loss, studies indicate that 18/6 intermittent fasting may provide important metabolic health and diabetes prevention benefits.
Fasting cycles have improved insulin sensitivity, allowing the body to regulate blood sugar levels better. In one study, 18/6 intermittent fasting reduced insulin resistance by 20-31% and lowered fasting insulin levels by 11-57% after just 5-12 weeks.
18/6 intermittent fasting may also support metabolic health by:
- Reducing oxidative stress
- Decreasing inflammation
- Improving good HDL cholesterol levels
- Lowering triglycerides
- Stabilizing blood pressure
Through these mechanisms, 18/6 fasting could help reduce the risk of chronic illnesses like type 2 diabetes and metabolic syndrome.
Anti-aging effects
Emerging research suggests intermittent fasting may slow aging processes and extend animal lifespan.
Studies link fasting cycles with enhanced autophagy, our cells’ innate self-cleaning process. This allows damaged proteins and organelles to be recycled into new functional parts. Fasting is also thought to trigger adaptive cellular stress responses similar to exercise-induced.
These anti-aging effects likely stem from giving digestive and immune systems periodic rest from food processing while activating hormone systems that enhance cellular repair. More human research is still needed, but the anti-aging potential of intermittent fasting is promising.
Heart health
Regular fasting cycles may support better heart health by improving certain cardiovascular disease risk factors.
Studies show that 18/6 intermittent fasting can lower blood pressure in pre-hypertension or stage 1 hypertension adults. Fasting may also optimize cholesterol levels and triglycerides when combined with a healthy diet.
Research indicates intermittent fasting reduces oxidative damage and inflammation involved in the development of atherosclerosis. This may provide protective effects against coronary artery disease.
By supporting healthy blood pressure, blood lipid profiles, and vascular function, 18/6 intermittent fasting offers heart health benefits for many people.
Cancer prevention
Intermittent fasting may aid cancer prevention and improve outcomes in patients undergoing chemotherapy.
Animal studies reveal fasting slows tumor growth by enhancing immune system function and reducing insulin-like growth factor 1 (IGF-1), a hormone that can promote cancer cell proliferation.
In human trials, fasting before chemotherapy reduced common side effects and enhanced the cancer-fighting effects of the drugs. More research is still underway, but time-restricted eating shows promise as a supportive strategy for oncology patients.
Reduce inflammation
Inflammation causes chronic diseases like heart disease, arthritis, and cancer. Intermittent fasting can lower the risk of developing these diseases by reducing inflammation. Studies show that intermittent fasting decreases inflammation markers, which improves overall health.
Increase energy levels
People who practice intermittent fasting often feel more energized. Fasting releases adrenaline and other hormones, boosting alertness and focus. It also helps regulate sleep-wake cycles, improving sleep quality and increasing energy levels during the day.
Improve sleep
A 6-hour eating window can improve sleep. Many people doing 18:6 end their meals early in the evening instead of eating before bed. Timing meals and avoiding late-night eating regulates sleep cycles, resulting in better quality sleep and more restful nights
Brain health
Fasted states enhance the growth of new brain cells and support cognitive function through various mechanisms:
- Increased brain-derived neurotrophic factor (BDNF)
- Reduced oxidative stress and inflammation
- Stimulates ketone production and neuronal activity
- Improved stress resistance
18/6 intermittent fasting may help reduce cognitive decline and neurodegenerative disorders like Alzheimer’s and Parkinson’s disease. However, human data is limited to small studies so far.
Typical 18/6 intermittent fasting schedule
When following an 18:6 intermittent fasting plan, you choose a 6-hour window to eat all your meals daily. The remaining 18 hours involve fasting.
Here is an example of how an 18/6 daily intermittent fasting schedule could be structured:
- 8:00 pm – Stop eating for the day
- 8:00 pm to 12:00 pm (16 hours) – Fast overnight
- 12:00 pm to 6:00 pm (6 hours) – Eat 2-3 meals within the 6-hour window
- 6:00 pm – Resume 18-hour fast
This schedule allows for a typical overnight fast followed by skipping breakfast. Lunch and dinner would be consumed between 12:00 p.m. to 6:00 p.m.
Many people adjust their feeding window to better fit their lifestyle and eating preferences. Some common options include:
- 9:00 am to 3:00 pm feeding window
- 12:00 pm to 6:00 pm feeding window
- 2:00 pm to 8:00 pm feeding window
As long as you fast for 18 consecutive hours and eat within a 6-hour window, you can modify the exact hours to suit your routine. The feeding window should contain all regular meals and snacks.
Following an 18 6 intermittent fasting plan
If you are new to intermittent fasting, adjusting to extended periods without food can take some time. Here are some tips for starting and maintaining an 18/6 intermittent fasting routine:
Start gradually
Don’t jump straight into an 18-hour fast – build up to longer fasting periods slowly. Begin with 12-14 hour daily fasts for 1-2 weeks, then extend to 16 hours for another 1-2 weeks before committing to an 18-hour fast. This allows your body time to adapt.
Stay hydrated
Drink plenty of non-caloric fluids like water, unsweetened tea, and coffee during the fasting window. This prevents dehydration and suppresses appetite. Add lemon, mint, or fruit infusions to make water more exciting.
Listen to hunger cues
Fasting from time to time is normal and even healthy. Don’t try to override true hunger signals within the 6-hour window. Eat enough nutrient-dense foods until satisfied – no need to count calories.
Choose nutrient-rich foods
Prioritize healthy whole foods like vegetables, fruits, lean proteins, legumes, nuts, and seeds within your daily eating window. Emphasize fiber and protein at meals to support satiation.
Avoid sweeteners
Don’t add sugar, artificial sweeteners, or sweetened creamers to beverages during your fast, as this may stimulate hunger and cravings.
Stay active
Continue regular exercise and activity as usual. Make sure to stay well hydrated during and after workouts on fasting days. Light walking during fasted hours can be enjoyable.
Allow occasional flexibility
Don’t be too rigid. Life happens, so if you need to shift your window earlier or later one day, just get back on track the next day. Allow a day off per week if desired.
Monitor energy levels
Make sure you have enough energy for your daily activities and workouts. Increase meal size or add snacks during the window if needed.
Consider supplements
Some people take electrolyte supplements to prevent fatigue, headaches and muscle cramps during fasting. Caffeine or green tea extract may also curb hunger.
With some patience and experimentation, an 18/6 intermittent fasting schedule can work well long-term. Pay attention to how you feel and adjust your eating times or portions to suit your needs.
What to eat during the 6-hour window
18 6 intermittent fasting focuses on when you eat, not what you eat. However, filling your 6-hour window with mostly whole, nutritious foods will provide far more health and weight loss benefits.
Aim to get a balance of lean proteins, healthy fats, high-fiber carbohydrates, and a rainbow of vegetables into your meals and snacks during the eating window.
Here are some healthy eating tips when following 18/6 intermittent fasting:
- Include a source of protein like eggs, chicken, fish, tofu, or beans in each meal.
- Fill half your plate with non-starchy vegetables at lunch and dinner.
- Choose whole grains like quinoa, brown rice, oats, and Ezekiel bread over refined grains.
- Snack on nuts, seeds, hard-boiled eggs, cut veggies, fruit, and plain yogurt.
- Eat healthy fats daily from olive oil, avocado, nuts, seeds, and fatty fish.
- Avoid added sugar and limit sweets to the occasional small treat.
- Cook meals at home as much as possible for control over quality.
- Avoid calorie-dense fried foods or heavy restaurant meals.
- Drink water, unsweetened tea, or coffee rather than juice, soda, or sweetened drinks.
While calorie counting isn’t required, be mindful of portions if weight loss is your goal. It’s easy to overeat in the shorter window when you get very hungry.
Sample weekly 18/6 intermittent fasting meal plan
To give you an idea of how meals and snacks could be structured, here is a sample one-week 18/6 intermittent fasting meal plan:
Monday
Fasting period: Dinner at 8 pm to Lunch at 12 pm
6-Hour Eating Window:
- 12:00 pm: Tuna wrap made with tuna, spinach, tomato, avocado, and hummus on a whole wheat tortilla plus a kiwi
- 3:00 pm: Natural almond butter and banana on Ezekiel toast, carrot sticks
- 5:00 pm: Chicken fajitas made with bell peppers and onions served in lettuce wraps with salsa, guacamole, and mixed greens salad
Tuesday
Fasting period: Dinner at 8 pm to Lunch at 12 pm
6-Hour Eating Window:
- 12:00 pm: Leftover chicken fajita salad
- 3:00 pm: Cottage cheese with mixed berries, a handful of almonds
- 5:00 pm: Veggie and chickpea curry over cauliflower rice with cucumber raita
Wednesday
Fasting period: Dinner at 8 pm to Lunch at 12 pm
6-Hour Eating Window:
- 12:00 pm: Greek yogurt bowl topped with raspberries, chia seeds and chopped walnuts
- 3:00 pm: Hard-boiled egg, raw vegetables and hummus
- 5:00 pm: Grilled salmon, sautéed kale, and roasted sweet potato
Thursday
- 12:00 pm: Lentil soup with carrot sticks
- 3:00 pm: Edamame beans
- 5:00 pm: Taco lettuce wraps (ground turkey, lettuce leaves, tomato, avocado, salsa, cheese) with roasted broccoli
Friday
Fasting period: Dinner at 8 pm to Lunch at 12 pm
6-Hour Eating Window:
- 12:00 pm: Leftover taco lettuce wraps
- 3:00 pm: Apple with natural peanut butter
- 5:00 pm: Vegetable fried brown rice with tofu and pineapple
Saturday
Fasting period: Dinner at 8 pm to Lunch at 2 pm
6-Hour Eating Window:
- 2:00 pm: Scrambled eggs with smoked salmon and avocado
- 5:00 pm: Chicken stir fry with vegetables over cauliflower rice
Sunday
Fasting period: Dinner at 8 pm to Lunch at 12 pm
6-Hour Eating Window:
- 12:00 pm: Mixed green salad with chickpeas, beets, walnuts and balsamic dressing
- 3:00 pm: Dark chocolate coconut bites (homemade fat bombs)
- 5:00 pm: Veggie pizza on a cauliflower crust with side salad
This sample meal plan provides a balanced mix of proteins, healthy fats, fiber-rich carbohydrates and unlimited non-starchy vegetables to promote satisfaction within the 6-hour window. Feel free to substitute other healthy meals and snacks you enjoy eating.
How to break an 18/6 intermittent fast safely
After completing an After completing an 18-hour fast, it’s important to break your fast properly. Here are some tips for ending your fast safely:18-hour fast, it’s important to break your fast properly. Here are some tips for ending your fast safely:
- Eat slowly and mindfully. Don’t overeat or rush food.
- Sip on water or herbal tea to rehydrate before eating.
- Enjoy a small snack first with protein, fat, and fiber, such as nuts or yogurt.
- Gradually introduce lighter foods before heavier meals. Soups, salads, or sandwiches are good first meals.
- Avoid overly processed junk foods. Refined carbs and sugar may cause energy crashes.
- Limit difficult-to-digest foods like fatty or spicy meals right after fasting.
- Wait 30-60 minutes before exercising after eating.
- Listen to your body’s signals. Eat more if you are still hungry after a light meal.
Properly breaking your intermittent fasting periods helps control hunger and prevent adverse effects like gastrointestinal discomfort, dizziness, or weakness.
Healthy lifestyle habits to pair with 18/6 fasting
To get the most out of an 18/6 intermittent fasting plan, pair it with other healthy lifestyle habits. Try to incorporate these:
- Stay active- Regularly exercise like cardio, strength training, and stretching. Light exercise during fasting hours can help manage hunger.
- Prioritize sleep – Aim for 7-9 hours per night to allow hormones and metabolism to regulate appetite and weight optimally.
- Manage stress- Uncontrolled stress triggers overeating and promotes weight gain. Practice relaxation techniques.
- Drink water – Stay well hydrated, especially during fasting hours. Herbal tea is also great.
- Eat plenty of vegetables – Non-starchy veggies are unlimited. They provide fiber and disease-fighting nutrients.
- Focus on nutrition quality – What you eat matters just as much as when you eat. Emphasize whole foods.
- Set reasonable goals – Expect to lose 1-2 pounds per week. The scale may not budge daily.
Establishing these additional healthy habits makes 18/6 intermittent fasting more sustainable and effective long-term.
Intermittent fasting 18/6 vs. 16/8
Intermittent fasting has become popular for its weight loss and health benefits. Two common approaches are the 18:6 and 16:8 methods. Both involve daily fasting periods longer than the typical overnight fast. But what exactly is the difference between these intermittent fasting protocols?
With 18:6 intermittent fasting, you fast for 18 hours each day and eat all meals within a condensed 6-hour window. For example, you might stop eating at 7 p.m. and not eat again until 1 p.m. the next day, giving you a 1 p.m. to 7 p.m. eating window.
The 16:8 method involves fasting for 16 hours per day and restricting food intake to an 8-hour window. A sample 16:8 schedule could be finishing dinner by 8 p.m., skipping breakfast, and eating between 12 p.m. to 8 p.m. daily.
The main difference is the length of the fast and the eating window. 18:6 provides a longer daily fast of 18 hours while allowing a shorter 6-hour eating window compared to the 16 hours fasted and 8 hours fed of the 16:8 method.
Both protocols will create a calorie deficit to promote weight loss. The longer 18-hour fast may be slightly more effective for fat burning but also more difficult for some people to follow. 16:8 fasting is a better option for beginners as it is easier to maintain. The best approach depends on each individual’s preferences and needs.
How much weight can you lose intermittent fasting 18:6?
Studies have been conducted on weight-loss results from different forms of fasting for various durations. In one study, participants followed a time-restricted fasting protocol for 12 weeks and lost an average of about 8.8 pounds. The protocol involved fasting for 16 hours and eating for 8, suggesting that even greater weight loss could be achieved with an 18:6 method.
How long does it take 18:6 intermittent fasting to work?
Nutritional advice is not one-size-fits-all because everyone’s body and lifestyle are different. The definition of “working” in terms of intermittent fasting varies for each person. Weight loss is one benefit of intermittent fasting, but it is not the only benefit. The 18:6 fast is more intense and can produce quicker and greater results compared to other types of fasting, according to Fung.
Who should not try 18/6 fasting?
While evidence suggests 18/6 fasting is safe for most healthy adults, certain populations should avoid this dietary strategy:
- Pregnant or breastfeeding women – Nutrient needs are increased to support fetal health and development.
- Adolescents under 18 – Require adequate nutrition to support growth and development.
- Those with a history of eating disorders – Intermittent fasting risks exacerbating disordered eating patterns.
- Individuals with diabetes – Fasting can increase the risk of hypoglycemia in people using insulin or other blood sugar-lowering medications.
- People with low body weight or malnutrition – Need adequate food intake to restore health.
- Those with gastrointestinal issues – Fasting may worsen conditions like reflux and ulcers.
Anyone with significant health conditions or taking medications should discuss the safety of intermittent fasting with their physician first. Listen to your body and stop the diet if you have concerns.
Potential side effects of 18/6 intermittent fasting
Making the switch to an 18/6 intermittent fasting schedule can take some adjustment. Fortunately, potential side effects are usually mild and often diminish within 1-2 weeks as the body adapts.
Possible temporary adverse effects may include:
- Hunger, food cravings, irritability – Especially during the first week of fasting. Stay busy and increase water intake to help curb hunger.
- Headaches – Can occur during the first few weeks. Make sure you are hydrating and getting adequate sodium.
- Constipation – Due to inadequate fluid intake. Drink plenty of water and eat fiber-rich foods.
- Fatigue and low energy – Your body needs time to adjust to using stored fat for fuel. Supplements or caffeine may help.
- Insomnia – Try not to eat right before bed to allow digestion to complete. Limit caffeine late in the day.
- Poor exercise performance – As your body adapts, you may need to reduce workout intensity temporarily.
- Binge eating – Difficulty controlling portions when very hungry. Practice mindful eating during the 6-hour window.
If side effects persist beyond the first couple weeks or become severe, 18/6 intermittent fasting may not be your best dietary approach. As with any diet, discuss potential concerns with your healthcare practitioner first.
In Summary
The 18/6 method of intermittent fasting involves fasting for 18 hours per day and eating within a condensed 6-hour window. This fasting approach may provide weight loss and metabolic health benefits for some people but also comes with precautions and possible side effects to be aware of. As with any dietary strategy, intermittent fasting requires patience and consistency to reap potential rewards.