Intermittent Fasting Suitability
Can I fast while breastfeeding?
Fasting is not recommended during pregnancy or while you are breastfeeding due to the risk of nutrient deficiencies. Breastfeeding increases your nutrient requirements substantially more than any other life stage, including pregnancy. During lactation, you will need to increase your calorie intake and variety of key nutrients, so fasting is not appropriate.
Is fasting okay if I’m trying to conceive?
There is a lack of research on the safety of intermittent fasting and conception. However, if you’re overweight, losing body fat may help improve fertility outcomes and offer other health benefits. Intermittent fasting may be a suitable approach for you, but best to talk to your health care practitioner to find the right fasting schedule for you.
Is fasting effective for overweight children?
No. Intermittent fasting is not appropriate for children due to the risk of nutrient deficiencies and the potential for unhealthy relationships with food. It would be more effective to look at ensuring they’re eating a varied, wholefood diet and eliminating any processed, sugar-laden foods such as with a low-carb diet approach.
My 16-year-old wants to try intermittent fasting. Is it an option?
Intermittent fasting is not recommended for teenagers, especially long periods of food abstinence such as a 24 hour fast. Not only are their nutrient intake required for their development compromised, but there is also some concern fasting can lead to eating disorders or disordered eating behaviour in teens. If it’s for weight loss, look at initiative eating for teens.
I have type 2 diabetes, is fasting a good idea?
Yes, intermittent fasting can be highly effective for type 2 diabetics particularly while following a low-carb diet or ketogenic diet. As with any dietary regime, it’s important to seek personalised advice from a nutritionist or dietitian before proceeding.
I am a type 2 diabetic and take blood sugar medication. Can I fast?
You need to be cautious with fasting for extended periods while taking blood sugar medication as your levels can drop and you can develop hypoglycemia. During your fast, it’s normal to expect your sugar levels to be low and your ketone levels to increase due to reduced caloric intake. It is recommended you consult your health practitioner before you start any fasting regime to see that it’s right for you.
I have a high training load, mainly resistance training, can I fast?
Absolutely. There is research to suggest working out while in a fasted state can actually improve your physical and mental performance as an athlete including your energy levels and endurance.
Types of Intermittent Fasting Methods
How do I choose which fast to do?
Fasting is as much a lifestyle change as it is a diet. Choose a fasting schedule that suits your lifestyle including your work, training and social commitments. If you’re new to fasting, try one that has a shorter fast time, to begin with.
What are the key differences between the 5:2 and the 16:8?
The main differences between the 5:2 and the 16:8 are the period of time fasted and calorie restriction. On the 16:8 you simply fast for 16 hours and eat whatever you choose in the 8-hour feeding window. The 5:2 stipulates you eat normally 5 days a week and consume about 500 – 600 calories two days a week.
What is fat adaptation?
Fat adaption is a term for the body’s ability to switch from using carbohydrates broken down into glycogen as the primary fuel source to burning fat. This process can take anywhere from 2 to 6 weeks, depending on the individual and their response to fasting.
Fat adaptation is the basic premise behind low-carb, high fat (LCHF) diets and the keto model.
I work night shifts, which fast would be most suitable?
It’s not uncommon for people who work night shifts to adopt a disordered way of eating or struggle with weight loss. This is often due to sleep deprivation and increased cortisol levels, as well as a poor diet and frequent snacking.
Fasting can be an effective tool to help improve overall wellbeing and stimulate body fat loss. The type of fast you choose will depend largely on your lifestyle commitments, but the attraction of intermittent fasting is that it is flexible.
When you schedule your feeding window is up to you as the time you eat may matter, but not a great deal according to the minimal evidence available. Try the 16:8 for a month and see how it goes.
Is there a minimum fasting time for weight loss?
Most of the research shows the benefits of intermittent fasting are typically seen with fasting for 14 to 16 hours at a time. However, in the case of the 5:2, an entire fast may not be necessary for everyone.
Depending on your goal and your current eating patterns, a short fast may help you get the results you desire. According to some research, 50% of Americans eat for 15 hours or longer daily (we dare say, these statistics are similar in Australia). Reducing that eating window by just a few hours may help stimulate weight loss and improve cognitive function amongst other things without prescribing to a fixed diet.
What’s the best fasting method to lose weight?
There is no “best” fasting method for weight loss. In fact, most fasting regimes when done correctly will result in weight loss.
Generally speaking, longer fasts can be more effective, however, it’s worth remembering the initial weight loss you experience quickly is often water. This is particularly the case for those on a standard Australian diet. After that, weight loss will slow but don’t let that discourage you as consistency will pay off.
If you’re not experiencing the weight loss results that you desire after a couple of months, try a new regime. Try longer fasts or shorter, more frequent fasting windows. Give the 5:2 diet a go where you’re restricting your calorie intake on set days.
Putting Fasting into Action
Can I take days off from fasting?
How you schedule your fasting days will depend on the intermittent fasting regime you have chosen to adopt. Some protocols suggest you fast every day for a period of time. Others like the 5:2 and alternate-day fasting, give you days off from your fast.
If you’re new to fasting, one of the easiest and most sustainable methods is the 16:8 which requires you to fast daily for 16 hours and enjoy an 8-hour eating window. Each person, however, is different. Try what works for your body and lifestyle.
What should I eat to break my fast?
The idea behind fasting is that during your eating window, you can resume your normal eating habits. So, you can choose to eat whatever you want!
However, it is recommended you choose foods higher in quality protein and dietary fat to help with blood sugar balance. This is particularly the case if you are breaking the fast shortly after training.
One of the appeals of intermittent fasting over a traditional diet is that no foods or food groups are restricted. However, if you’re fasting for overall health and weight loss, it is important to adopt a nutritionally balanced diet during your feeding windows.
How can I handle my cravings and hunger pangs when fasting?
Keeping hydrated throughout your fast is extremely important and effective if you experience hunger pangs. Herbal tea or adding lemon or Himalayan salt to your water can be helpful.
Some fasting methods will allow you to drink bone broth. Others, like the 5:2 are allowing you to eat a small number of calories. If you do experience cravings during these fasts, listen to what your body may be craving for.
Keeping busy and practising self-care during your fasting times can also be helpful.
Should I exercise during the fasting window?
Exercising while fasting may not only speed up your fat-burning process but also lead to greater endurance long term and increase the positive effects of intermittent fasting. In fact, some athletes fast for 24 hours before exercising and then consume a high protein meal.
If you’re new to fasting and haven’t become fat-adapted, listen to your body carefully when doing strenuous exercise. For some, the depleted glycogen stores can result in weakness, nausea or feeling faint initially.
My blood sugar levels drop during the fasting period, is this okay?
Yes, it is common to see blood sugar levels reduce during fasting. If you have a pre-existing medical condition, monitoring your sugars carefully should be advised.
Can I take medications during my fast?
This depends on the type of medications and your condition. Many medications shouldn’t be taken on an empty stomach and due to a change in your blood sugar levels, your medications may need to be adjusted.
It’s important to speak to your health care practitioner before commencing a fasting protocol if you are on regular medication.
Will I lose muscle mass while fasting?
There is minimal, if any, muscle loss during short-term fasting. This is because your body first breaks down glycogen into glucose for its energy. Once that’s all used up, the body uses fat for fuel. Typically, your body won’t use excess amino acids and energy from muscle unless it really needs to. This is generally not the case in those with excess body fat.
Research suggests short fasts increase your ability to burn fat while helping you to control your glucose and insulin levels. Hormonal changes occur that may actually help with muscle growth but not by much.
Longer fasts may affect your muscle mass largely due to poor nutrient intake during the feeding window. Timing of your meals, such as eating a protein-rich meal after exercise, will help with muscle recovery and preservation.
Will fasting affect my hormones?
Intermittent fasting can have a positive impact on your hormonal health indicators, in particular insulin sensitivity. Fasting is likely to have an effect on your sex hormone production including testosterone, oestrogen and progesterone, as well as the hormones DHEA, LH, FSH and cortisol.
For men, planned refeeding and correct nutrition can help overcome any side effects such as mood swings, fatigue and low sex drive. For women, fasting can be more serious when it comes to hormone health.
Extended fasts can signal that you’re experiencing a famine and impair normal hormone synthesis. The most obvious indicator of hormone disruption is irregular or non-existent periods.
Gentler fasting approaches and a diet that is rich in protein and healthy fats are much more suitable for women. It is these protocols we see the promotion of weight loss, improved detoxification, enhanced cognition. You may find these protocols also offer therapeutic benefit to conditions such as Polycystic Ovary Syndrome (PCOS).
What if I don’t see any results?
If you’ve given intermittent fasting adequate time and you’re not seeing results, change it up. Try a different protocol, experiment and make sure you’re recording your stats and progress. Alternatively, seek some advice from a qualified nutritionist or dietitian to help you individually tailor it to your needs.
Dietary Advice While Fasting
Can I drink coffee during my fast?
Drinking coffee will depend on the fasting regime you choose. Most suggest coffee is part of the allowed liquids including plain water, unflavoured sparkling water, herbal tea and black tea. Some may even allow you to have a coffee with MCT oil or butter.
Can I combine keto with intermittent fasting?
Yes, you can adopt a keto diet and fast. In fact, by consuming a low carb, high-fat diet (LCHF) and intermittent fasting you may switch to a fat-burning machine more quickly and work more efficiently. This can often yield results much faster when done correctly.
Is it okay to eat anything and as much of it as you like in the feeding window?
This depends on the type of intermittent fasting plan you’re doing as well as your health goals and values.
Some plans like the Warrior Diet actually encourage overeating in the feeding window. Others, like the 16:8, don’t prescribe any dietary advice outside of fasting for 16 hours and eating within the 8-hour window.
If you’re wanting to lose weight, what and how much you eat during the feeding window may affect your results. At the end of the day, your calorie intake will matter if it’s more than your calorie output. Likewise, if you want to improve your insulin sensitivity, intermittent fasting can only do so much if you’re still eating a high-sugar, highly refined diet.
Can I snack during the fast?
If you’ve chosen the 5:2 method or the 20:4 fast, you can consume low-calorie snacks during the fasting period. Other methods require you to do a clean fast only drinking zero-calorie beverages such as water, herbal tea and black coffee.
Is it okay to skip breakfast?
The old saying ‘breakfast is the most important meal of the day’ doesn’t necessarily ring true for fasting advocates. In fact, some people find they perform better in the morning in a fasted state.
The idea behind most intermittent fasting regimes is that it’s flexible. If you enjoy it and find you need breakfast to get up and go in the morning, schedule your fasting window or lower-calorie meal for later in the day. Most people, however, find skipping breakfast an easier and more sustainable option.
The key things to consider in scheduling your eating window are:
- What do you prefer – fasting in the morning or sleeping on an empty stomach?
- What time do you prefer to workout?
- What are your social / lifestyle commitments?
Explore in more detail
- A Beginner’s Guide To Intermittent Fasting
- A Guide To The 16:8 Fast
- A Guide To The 20:4 Fast
- A Guide To The 5:2 Fast
- Intermittent Fasting And Exercise
- Intermittent Fasting And Hormone Balance
- Intermittent Fasting And Keto
- Intermittent Fasting And Type 2 Diabetes
- Intermittent Fasting And Weight Loss
- Intermittent Fasting: Tips To Starting Your First Fast
- Side Effects Of Intermittent Fasting
- Tips For Intermittent Fasting Success
- Top FAQs Of Intermittent Fasting