5 Top Tips on Intermittent Fasting


Many people are trying intermittent fasting for many reasons, but typically to lose or manage their weight.  They may also try fasting to feel as if their body is being cleansed, or to tap into excess fat stores during the fast, to get in touch with their hunger, or possibly just to try something new.   Who doesn’t like a challenge?  But what is intermittent fasting?  Intermittent fasting means that you fast for an extended period of time, usually 16 – 18 hours daily, which leaves only 6 – 8 hours to consume your daily energy requirements.  Usually people will start fasting at 8 pm and break the fast about noon or 2 pm the following day.  Water and non-calorie drinks (sugar free drinks, black coffee, teas are usually allowed) during the fasting period.  Fasting can be for religious reasons such as during the holy month of Ramadan, or it could be 5:2 (5 days off, 2 days on), cyclic IF, daily fasting, alternate day fasting, random fasting, fruit fasting, water fasting, fast 5…the list goes on.   

TOP TIP # 1 - Energy In = Energy Out               

Be mindful of how much energy you are consuming.  There are plenty on online calculators that will help you work this out and a good calculation will use your age, gender, height and weight.  If in doubt then roughly 30-35 kcals/kilogram body weight is a rough guide to get you started.  For a 70 kilogram person this equates to 2100 – 2450 kcals daily.  Obviously this is a rough guide because if you train or are very short or very tall this will over or under estimate what you may actually need.

TOP TIP # 2 - How to break the fast

Try to consume nutritious food during the non fasting window due to a limited time to eat.  Eat healthy foods that meet your estimated energy requirements.  If you are trying to lose weight then calculate for this also.  It can be difficult to consume your daily energy requirements in half the time you would normally and as a result you probably can’t = hence you lose weight.  If weight loss is not your goal then you will need to maximise your food intake in your eating window.  

TOP TIP # 3 - Fat Burn         

 Do you really burn fat when you are fasting?? If you consume carbohydrate during your non-fasting window it is unlikely you are burning much fat in the fasting period, as this requires you to be in a carbohydrate depleted, fat adapted state of nutritional ketosis.  You will burn some fat as fuel in the fasting period, but not as much as a fat adapted person.  If you want to be in ketosis you don’t have to fast to achieve this, it’s a different dietary principle; however when you are in ketosis it is possible to fast a little more easily as your body can efficiently run on ketones (broken down from fat stores to release energy) and thus use body fat stores for energy. 

TOP TIP # 4 - Fasting and exercise

Yes you can train when fasting and it is encouraged if you are able to.  Exercise combined with fasting may mean that your glycogen stores are depleted faster and therefore more fat is used for fuel.  You should consume water throughout the activity and fasting window as dehydration could be very dangerous for most people…you need to replace your sweat.  During Ramadan food and water is not consumed during daylight hours, and therefore training programmes are usually adapted to be in the evening after Iftar or early morning light sessions after Sahoor;  but hydration will be an issue after an early morning session as no fluid is allowed.  It is usually recommended to do evening training sessions for Ramadan, before or after Iftar.  Some training Intermittent Fasting protocols recommend that if you are training during the fast then some 100% whey protein consumed after a session may be allowed…so not a typical fasting protocol but another point to consider for athletes who want to try intermittent fasting,  as weight loss may not be a goal and lean body mass gain is. 

TOP TIP # 5 - Is it healthy?    

Actually there is nothing wrong with fasting for most people.  If you take medication or have a medical condition where you need regular amounts of food and fluid throughout the day then it is not recommended.  Fasting is a way of life and for most people helps them achieve and maintain a healthy weight.  As long as you eat nutritious food in the non-fasting period and can achieve your health goals it should be fine to do, if in doubt check with a health professional.  Just like any eating plan Intermittent Fasting is not for everyone, but for some it can be life changing and an easy method for calorie control, and for a feeling of cleansing and improved energy. 

March 20, 2019