Intermittent fasting is a dietary approach that cycles between periods of eating and fasting.
There are a number of different approaches of intermittent fasting, and the two most well-known are:
- 5:2 – The 5:2 approach limits calorie intake on two non-consecutive days per week to 500kcal per day for women and 600kcal per day for men and recommends following a healthy balanced diet for the remaining 5 days of the week.
- 16:8 – The 16:8 approach involves eating during an eight-hour window in a day and fasting for the remaining 16 hours. For example, you could eat from 10am to 6pm and then drink non-caloric beverages during the fasting period, such as water, tea and coffee.
What are the benefits of intermittent fasting?
Intermittent fasting gives your body longer breaks from digesting food, potentially leading to consuming fewer calories when compared to regular eating patterns. This can aid in weight management and help regulate blood sugar levels, which is beneficial for those with prediabetes or type 2 diabetes. However, it’s important to be mindful of what you eat during non-fasting periods, as overeating or consuming high-calorie foods can hinder weight loss goals. Other potential benefits of intermittent fasting may include improved gut health, better sleep, lower blood pressure, and decreased inflammatory markers associated with many chronic diseases.
Is intermittent fasting for everyone?
Intermittent fasting may have some potential side effects, especially if your eating windows are overly restrictive or the meals consumed during these windows are unbalanced. Some of the common side effects of intermittent fasting include:
- Headaches, problems concentrating, cognitive fog, irritability and feeling faint and tired particularly during the initial stages of intermittent fasting, as the body adapts to using stored energy during fasting periods.
- During fasting periods, especially when first starting fasting, you may experience increased hunger and cravings as your body adjusts to the new eating pattern.
- Intermittent fasting may cause digestive discomfort, such as bloating, constipation, or diarrhoea in some people, so it may not be suitable for individuals with gastrointestinal conditions such as IBS (irritable bowel syndrome).
- Intermittent fasting may trigger or exacerbate disordered eating patterns, such as binge eating or restrictive behaviours, so it is not suitable for individuals with a history of eating disorders or disordered eating. If you experience any concerns about your eating habits, please refer to the signposting document available in the Wellbeing Way app.
Intermittent fasting may also not be suitable for individuals with pharmacologically controlled diabetes, who are pregnant or breastfeeding, underweight, or taking medications that need to be taken alongside food. If you are interested in intermittent fasting but are not sure if it would be suitable for you, it is important that you talk with your GP or medical team before starting this dietary approach.
Tips for successful intermittent fasting:
- Start by picking your chosen schedule. This could involve deciding when your 8-hour eating window will begin and end each day, or which days that week will be most suited as your two fasting days, if you are following a 5:2 fasting pattern. Remember that fasting days can differ from week to week and don’t need to be consecutive. Be realistic with yourself when choosing your schedule. Check your diary and look at your daily routine and choose the schedule which will work best with your lifestyle.
- Pay attention to your body’s hunger and fullness cues. If you feel overly hungry or unwell during fasting periods, it’s okay to adjust your eating schedule or consider a different fasting method.
- You don’t have to be perfect! You can choose to take days off when you have social events or when your body tells you it needs more nutrition, but it’s worth being mindful of how often you do this. If this happens more often than not, this is a sign that intermittent fasting might not be for you!
- Plan your meals and bulk cook in advance to ensure that you have healthy meals readily available and that you’re getting all the nutrients your body needs. This will help prevent overeating or choosing unhealthier food options during eating windows.
- Make sure your meals are rich in nutrients from all food groups. Include plenty of fruits, vegetables, lean proteins, and healthy fats in your meals. Create satiating meals by including fibre and protein-rich foods to help manage hunger and cravings during fasting periods.
- Be mindful of portion sizes and practice portion control to avoid overeating, especially if weight loss is your main goal.
- Make sure you are hydrated by drinking plenty of water, herbal tea, or other non-caloric beverages during fasting periods.
- Avoid high-intensity workouts during fasting days/periods.
- Get enough sleep and make sure you have time to relax.
- Manage your stress levels. High levels of stress and poor sleep can make intermittent fasting more challenging. Practice stress-reducing activities such as meditation, deep breathing exercises, or mindfulness to support your fasting journey.
Intermittent fasting can be helpful for weight loss and maintaining a healthy weight, as well as potentially improving other aspects of your health such as blood pressure and insulin sensitivity. Regardless of which dietary approach you stick to, it is important to aim for a balanced and nutritious diet, try to meet physical activity guidelines and address other lifestyle factors such as good sleep hygiene and managing stress for long term health and improved quality of life.
Further reading:
https://www.diabetes.org.uk/diabetes-the-basics/type-2-remission/intermittent-fasting-for-remission
https://www.bhf.org.uk/informationsupport/heart-matters-magazine/nutrition/ask-the-expert/fast-diet
https://www.diabetes.co.uk/diet/time-restricted-eating.html