Given the popularity of various intermittent fasting regimens, it’s likely you’re eager to give one a try and explore the health advantages it promises.
Health and fitness experts have explored a variety of diet strategies to cater to diverse health requirements and preferences. Having been there myself, I know how hard it is to pick a suitable IF plan. Beginners are not even sure if their bodies can tolerate intermittent fasting in the first place.
Drawing from ten years as a health and nutrition specialist, I’ve adopted the 18/6 intermittent fasting method. This approach has clearly enhanced my skin health and mental acuity. However, I found it challenging to fit my nutritional requirements within the 6-hour eating window.
This is a thorough guide on undertaking 18/6 intermittent fasting, including what you can and cannot eat and the benefits and possible downsides. I will conclude my article with tips for better results and reducing side effects.
18/6 Intermittent Fasting: Overview
Among the time-restricted fasting plans, including 16/8 and 14/10, 18/6 is the most rigorous. The eating/fasting window of an average American who is not fasting is 12 hours. Extending it to 14 or 16 hours is less taxing than choosing an 18-hour fast.
In an 18/6 fasting plan, you fast for 18 hours and eat in a 6-hour window. There are no hard rules on when precisely your 6-hour eating window should begin or end.
Many individuals opt for a later breakfast, aligning their six-hour eating period with the middle of their active day. You can choose your eating window based on your schedule and what works best. It is better not to be famished too close to your deep work hours since you might have difficulty concentrating.
If you have a 9 to 5 work schedule, you can have your first meal around 11 a.m. and start fasting after 5 p.m. By postponing your breakfast you can extend your eating window to cover a substantial part of your evening, leading up to bedtime.
Why 18/6 Fasting?
It is an obvious question that would come to your mind. Why starve yourself for 18 hours when you can go with a 16/8 and even less taxing 14/10 fasting plan?
Beginners should start with easier fasting methods. The 14/10 and 16/8 IF methods are more practical options as they prepare your body for longer fasts. This will help you gradually adapt to the extended 18/6 fasting schedule.
The 18/6 IF method is ideal for someone who has hit a weight-loss plateau with 16/8. It can provide additional benefits such as detoxification through autophagy and a complete reset for the gut.
Typical IF benefits, such as slowed aging, lower inflammation, and improved cognitive function, become more pronounced with longer fasting intervals, such as 18/6.
What to Eat During the 6-hour Eating Window?
Intermittent fasting appeals to many people because your diet is not restricted. You can eat anything in the eating window.
But again, you should take this statement with a pinch of salt. It’s essential to focus on nutrient-rich meals, making sure you meet your body’s nutritional needs during that brief eating window.
Your eating plan has to work in tandem with your health and weight-loss goals.
Indulging in empty calories and processed foods can lead to quick fatigue, depriving your body of the energy needed to maintain the fast effectively. You must eat to keep your blood sugar levels stable to avoid throbbing headaches, weakness, and fatigue.
Focus on healthy fats and lean proteins — so try finding foods that keep you full for a long time. Avoid pasta and cereals in breakfast and replace them with fiber-rich carbohydrates such as quinoa, beans, lentils, and sweet potatoes. Eggs, yogurt, tofu, avocados, nuts, and fatty fish are other excellent sources of lean proteins.
Dark chocolate with 70% cocoa and less sugar is an excellent source of healthy fat. It is rich in fiber, antioxidants, and nutrients like iron and magnesium. It is also a rich source of dietary flavonoids and produces nitric oxide, which is good for your vascular function. But if you strictly want to limit your calorie intake, you should avoid chocolate. (1)
Beverages While Fasting
It’s vital to remember that maintaining proper hydration is essential when fasting in the 18/6 window. You can have lemon water since it has a trace amount of calories, but if you are on a strict IF regime, you must limit yourself to plain water.
Many people come to me with this question about whether they can have their morning coffee while fasting. Coffee can help people postpone breakfast to quite an extent. I have both good and bad news for you when it comes to coffee and fasting.
Yes, you can have black coffee without the creamers, milk, or sugar while fasting, as it won’t induce any metabolic changes. Similarly, it is okay to have herbal teas and other calorie-free beverages.
Now, turning to diet soda, it’s important to understand that just because it’s labeled as “diet” doesn’t automatically qualify it for consumption during fasting periods.
Diet soda contains artificial sweeteners that stimulate the mTOR, making it unfit for fasting. But again, if you are flexible with your fasting, you can have 1-2 cans a day without majorly disrupting your fasting plan. But if you ask me, it is best to avoid it, since it absolutely does no good to your health.
Sample Meal Plan
Six hours is quite a small time window for effectively spacing out three regular meals. Overeating in one meal doesn’t help since you will have difficulty eating again within the eating period. Therefore, it’s essential to carefully select your meal plan to provide your body with the necessary nutrition, making it easier for you to navigate through your fasting period effortlessly.
Here is a sample meal plan. Please note you can have calorie-free beverages at any time within your eating period.
Early eating window meal plan:
- 8 a.m. — Chicken egg scramble with mixed veggies and wheat toast
- 10 a.m. — Mixed berries
- 12 p.m. — Tofu with veggies, fish, or oats.
- End at 2 p.m. — Cottage cheese with stir-fried veggies and full-fat unsweetened yogurt
Midday eating window meal plan:
- 11 a.m. — Apple and a granola bar
- 1 p.m. — Mixed fruit salad with peanut butter and chicken curry
- 3 p.m. — Tofu and lettuce sandwich with whole wheat bread
- End at 5 p.m. — Lentil soup, baked beans and rice
Late eating window meal plan:
- 1 p.m. — Chicken/turkey sandwich with whole wheat bread
- 2 p.m. — Cottage cheese with rice cake and veggies
- 4 p.m. — Soup with lots of veggies or mixed fruit salad
- End at 6 p.m. — Zucchini noodles or vegetable rice
Benefits of 18/6 IF
Weight loss is the primary benefit and reason most people take up 18/6 fasting.
You must plan your meals to meet your six-hour deadline, which makes you a mindful eater. It is the first step to losing weight and getting healthy, whether you are fasting or not.
After adhering to the 18/6 fasting approach for several weeks, you may notice a visceral and abdominal fat reduction. Besides, you will have all the generic benefits of intermittent fasting, which are:
Fasting triggers autophagy or cell cleanup. It is a process where the body discards the defective cell components and recycles usable matter.
Further, it can activate the NRF2 (Nuclear factor erythroid 2-related factor 2) that regulates anti-inflammatory genes and reduces inflammation, cardiovascular diseases, and oxidative stress, the cause of various pathological conditions. (2)
Better Cognitive Function
Studies have shown a correlation between fasting and cognitive dysfunctions such as dementia, Parkinson’s, and Alzheimer’s disease. Obesity, insulin resistance, and upset metabolism are by-products of reduced brain power. Fasting works on all these concerns directly and indirectly.
When paired with a keto eating pattern, fasting stimulates ketone production, boosting neural metabolism with mental clarity. Moreover, fasting increases the production of human growth hormone by affecting the BDNF (Brain-derived neurotrophic factor). (3)
Research has a conflicting opinion on whether fasting kills or multiplies tumor cells. While some studies advocate that autophagy — triggered by fasting — restricts the multiplication of tumor cells, others indicate it can have an adverse effect.
Experts believe autophagy is triggered at least after the 12-hour fasting mark. Research on breast cancer showed prolonged nightly fasting reduces the risk of breast cancer re-occurrence. (4)
Optimal Frequency of 18/6 Fasting For Maximum Benefits
While there’s no one-size-fits-all duration for the 18/6 fasting method, you might contemplate practicing it on alternate days or a few times per week. It all depends on how well it suits your body.
Women must be extra careful since they are vulnerable to hormone fluctuations. If you are pregnant or breastfeeding, you should avoid it. Due to their intense nutrition requirements, 18/6 is not meant for children and teens.
If you have chronic eating disorders or have serious health issues related to the heart, lungs, or liver, you can consider more flexible and easier diet plans.
Women around menopause should undertake fasting under a doctor’s supervision. You should find ways to manage stress, watch your sleep cycle, and ensure proper nutrition.
Also, if you exercise, you should watch out for signs of excess fatigue or weakness and adjust your eating plan and nutrition accordingly.
Side-Effects of 18/6 Intermittent Fasting
With intermittent fasting, one thing is for sure. You should be prepared to deal with hunger pangs. A frequent error is to overeat as soon as the eating window opens, which defeats the purpose of fasting.
Consuming high-fat foods when breaking your fast can lead to digestive problems like constipation, acidity, and bloating. Some experts recommend a Mediterranean diet, which includes whole grains, fruits, vegetables, seafood, beans, and nuts post-fasting. (5)
Athletes may experience a decline in performance during fasting, particularly when engaging in high-intensity workouts.
Exercising right after your eating window closes can challenge your body to meet heightened nutritional needs. It’s often preferred to exercise following the first meal during the eating window.
Going to bed hungry can lead to sleep difficulties. Adjusting your eating schedule to sync with your bedtime might be wise.
Some people might face detox reactions like difficulty concentrating, headaches, and skin rashes while fasting. Your body might be unable to sustain the nutrition deficiency and have to deal with hypoglycemia. Re-think your plan or avoid IF if your blood sugar levels are beyond control.
My Quick Tips For 18/6 IF
After considering everything, if you have decided to take the plunge, here are some tips to help you sail through your fast smoothly:
- Go to bed early to avoid late-night hunger and binge eating.
- Limit processed foods.
- Take it slow, start with a 12-hour fast, and gradually scale up.
- Stay hydrated to keep your electrolytes in balance.
- Begin with a strong why, and write down the reasons why you’ve chosen to embark on this fast.
- Plan your meals and eat nutrient-rich foods that keep you full for longer.
- Exercise and practice mindfulness.
- Do not overstuff yourself in the eating window.
- Eat an appropriate amount of fiber to avoid bowel issues.
- Prefer exercising during the eating window.
Can I do an 18/6 fast every day?
Yes, you can if you are already familiar with fasting. However, beginners should always consult an expert before taking up daily 18/6 fasting. After the initial adjusting phase, if you encounter notable health issues, it’s advisable to consult your healthcare provider.
What results can I expect from 18/6 fasting?
You can expect weight loss, better skin, and improved oxidative stress markers. However, results might differ depending on your body type, gender, and eating preferences.
How do I get my body ready for 18/6 fasting?
You can start with shorter fasts before taking up 18/6 fasting. If you can navigate them seamlessly, you are likely fit for 18/6 fasting. It’s best to talk to a health expert to understand the possible health issues and how to deal with them.
An 18/6 fast can be fantastic for your weight loss goals. But not everyone can sustain it. Try various fasting schedules with different lengths to discover the best approach for you.
Be mindful of your body’s cues to decide whether to continue fasting or not. It’s advisable to start the fasting routine gradually, allowing your body time to develop the resilience required to go without food for longer periods. You should re-align your expectations if you feel irritable and worked up all the time, even after the initial fasting phase.
If you can sustain 18/6 IF, there is nothing like it to achieve your weight loss goals.
- Bondonno, C.P. et al. (2015) Dietary flavonoids and nitrate: Effects on nitric oxide and vascular function, OUP Academic. Available at: https://academic.oup.com/nutritionreviews/article/73/4/216/1817794 (Accessed: 14 January 2024).
- Saha S;Buttari B;Panieri E;Profumo E;Saso L; (no date) An overview of Nrf2 signaling pathway and its role in inflammation, Molecules (Basel, Switzerland). Available at: https://pubmed.ncbi.nlm.nih.gov/33238435/ (Accessed: 14 January 2024).
- Abdulsada MM, Wilhelm ZR, Opekun AR, Devaraj S, Jalal PK, Mindikoglu AL. The effect of four-week intermittent fasting from dawn to sunset on circulating brain-derived neurotrophic factor levels in subjects with metabolic syndrome and healthy subjects. Metabol Open. 2020 Dec 4;9:100070. doi: 10.1016/j.metop.2020.100070. PMID: 33376976; PMCID: PMC7758552.
- Marinac CR, Nelson SH, Breen CI, Hartman SJ, Natarajan L, Pierce JP, Flatt SW, Sears DD, Patterson RE. Prolonged Nightly Fasting and Breast Cancer Prognosis. JAMA Oncol. 2016 Aug 1;2(8):1049-55. doi: 10.1001/jamaoncol.2016.0164. PMID: 27032109; PMCID: PMC4982776.
- Lăcătușu CM, Grigorescu ED, Floria M, Onofriescu A, Mihai BM. The Mediterranean Diet: From an Environment-Driven Food Culture to an Emerging Medical Prescription. Int J Environ Res Public Health. 2019 Mar 15;16(6):942. doi: 10.3390/ijerph16060942. PMID: 30875998; PMCID: PMC6466433.
Article Updates Timeline:
Our editorial team experts constantly update the articles with new information & research, ensuring you always have access to the latest and most reliable information.
January 26, 2024
Dr. Rashmi Byakodi
Fact Checked By