5:2 Fasting. Will it work for you?

Intermittent fasting. (IF)

It seems to be a hot topic in the media at present. I thought I would do a little lesson for you all to make things a bit clearer.

Intermittent fasting is simply having time periods in your week that you eat, and other time periods in your week where you don’t.

Fasting is not new, people have been fasting for 1000’s of years for health, cultural and religious reasons.  In actual fact, we all fast whilst sleeping. That’s how breakfast got its name. It’s when we BREAK our FAST.


There are many different forms of fasting, however in order to keep this blog post short and sweet, I will focus on the 5:2 protocol. I am going to solely focus on its weight loss benefits as that is my area of expertise.


Before I begin. lets have a little reminder about how all weight loss works.

Weight loss occurs when we burn up more calories than we put in each week. .

The technical term is to create a calorie deficit.

Intermittent Fasting is simply a tool that can help us arrive at that weekly calorie deficit.

Prefer to watch?


Let’s look at twin sisters Fiona and Tracy (same height, weight, age etc)

Tracy and Fiona both burn 2000 calories per day or 14000 calories per week if you want to look at it as a weekly total.

**You  can get a rough estimate of how many calories you burn each day HERE 

They need to consume 2000 calories per day (14000 per week)  in order to maintain weight. Technical term for this is calorie balance.  

Same calories IN +   Same calories OUT = weight maintenance.

**It helps to always look at a weekly average, not micro-manage each meal or even each day.

If Fiona and Tracy want to lose weight, they need to consume LESS than 14000 calories per week.

Let’s assume that they want to lower their calorie intake by 3500 calories per week in order to lose half a kilo. This means they now need to eat 10500 calories each week, instead of their normal 14000 maintenance level.


There are a number of different ways to achieve a calorie deficit…

I will look at just 2 of those ways in order to keep things simple.

1) Traditional dieter Tracy –

traditional dieter tracy

This protocol means that Traditional Tracy needs to be a little bit diligent every day.


2) 5:2 Fasting Fiona –

fasting fiona

Fasting Fiona only needs to use will-power and diligence on 2 non-consecutive days out of her week instead of 7.

The bad news is that she may need LOT’s of it during those 2 days.

Most days of her week, she can continue with her normal routine (hence no will-power needed)


For some people the fast feels relatively easy and simple. It actually feels like a freedom from eating and thinking about food all of the time.

For others, the fasting day feels very stressful and actually results in them binging and eating MORE on all other days.

The weekly result is the one that matters most.


If fasting feels natural to you and results in less weekly calories, then I say go for it, give it a try.

If fasting feels stressful to you and results in more weekly calories (due to over eating on other days), then I say give it a miss and stick with protocol 1.



Side note –

Traditional dieter Tracy has the view that Fasting Fiona is starving herself or doing something radical or weird. When in actual fact, Fiona and Tracy are actually consuming exactly the same amount of calories over their week. Fiona is simply allocating hers in a different way.

The TOTAL number is what's important

Of course she (or you) could do a combination of the 2.

Knowing that there is NO perfect pattern, only the pattern that best helps YOU achieve a calorie deficit at the end of each week.



Because you are limiting calories over the week, what you eat becomes MORE important, not less.

You now have limited opportunity to get your essential nutrients in. In particular protein rich foods, fibre rich foods, some healthy fats and vegetables.

If you do NOT consume adequate protein over your week, you will lose weight, but a lot of it may come from lean muscle mass  not excess body fat.

Who should NOT fast.

    • Anyone with medical issues – check with your Doctor first
    • Anyone with prior eating disorders (particularly involving restriction)  or emotional issues with food
    • Anyone with low blood sugar issues – again check with your Doctor
    • Pregnant or breast-feeding
    • Kids – they are still in the growth stage
    • Anyone already underweight
    • Anyone who strictly sticks to a low (deficit) calorie limit on all other days.


Would you like coaching with intermittent fasting?

I have helped 100’s of people get started, master this skill and avoid the common pitfalls to achieve the health and body they want.

>>> First steps to Fasting <<<



Chriss TinslayWith 20 years experience, Chriss Tinslay is one of Australia’s leading Personal Trainers.
Chriss started her career into the fitness and personal training industry in 1994  as a receptionist at the local gym she attended and loved.
She runs a revolutionary new habit change coaching program Healthy Happy Habits, teaching you how to transform your body and your life by making ONE small simple change at a time

Chriss believes that fitness and fat loss should fit into your fabulous life, NOT take over it.   You can connect with her on Facebook where she shares useful tips each and every day.



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