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Fast approaching Christmas

Our nutrition staff turn their attention to the next and final eating approach - 5:2, sometimes referred to as ‘intermittent fasting’. Find out how they went!

Find out the heart foundation's views on teh 5:2 diet

After a month of trying out Paleo and then Low Carb High Fat, we thought it was time to turn our attention to the next and final eating approach - 5:2, sometimes referred to as ‘intermittent fasting’.

To recap, a group of Heart Foundations dietitians and nutritionists have been trialling some of the most popular dietary trends around. Our goal was to gain a personal insight to the challenges, benefits and sustainability of the various approaches. Each dietary approach was trialled for a month. 

What is the 5:2 or intermittent fasting diet?

This approach involves following a healthy eating pattern for five days, then cutting calorie intake down to a quarter of that for two days of the week. This means eating 500 calories (2,100 kilojoules) a day for women and 600 calories (2,500 kilojoules) for men. It is not recommended to have the two fasting days together.

The theory behind intermittent fasting is that eating less is easier to do when applied to two days of the week, rather than having to cut calories every day. The idea is that by doing so, followers will consume fewer calories overall during a seven-day week than they ordinarily would thus leading to weight loss.

Personal experiences of 5:2


I didn’t view the 5:2 approach with the same level of enthusiasm as I did the Paleo or Low Carbohydrate High Fat trial. The thought of having to limit even healthy food during fasting was something that I was dreading – maybe I just love food a bit too much! I chose Tuesday and Thursday for fasting which are days that typically don’t involve some high-intensity exercise. Over three weeks, I only managed to complete one full day of fasting. I mostly failed at about 4.00 pm due to low energy levels, an inability to concentrate and the thought of child pick-up time looming. On the days before and after fasting, I felt as though I wanted to compensate by overeating or eating less healthy choices. While I acknowledge the 5:2 or intermittent eating approach may work for some, I prefer a far more consistent approach to eating over seven days a week. I also look at food as much more than calories and enjoy the flavour, creativity and spontaneity of eating it.


I had a lot of difficulty with the 5:2 eating plan, partly because I am so accustomed to eating regularly and I didn’t agree with the rationale behind the diet. In saying that, I can be pretty determined and did manage to complete most of my fasting days. Some of the changes I had adopted during the LCHF and paleo approaches were thrown out the window during 5:2. During the fasting days, I felt like I needed to drink cups of black coffee to replace the food I wasn’t eating. I would also eat higher calorie/less healthy food options both the day after and day before fasting. Overeating before and after each fasting day would clearly be counterproductive, if I was doing the 5:2 approach for weight loss. Eating wasn’t enjoyable during the fasting days and I had challenges concentrating and maintaining a positive mood and energy levels. This eating regime may work for some people but it definitely didn’t work for me.


I was really looking forward to trying this dietary approach, thinking it would provide a lot more flexibility than the previous eating plans trialled. The first couple of days were great. Then came the day before fasting and my self-control dissolved completely. I found myself eating more high sugar and high fat snacks, in the knowledge that the next day I would be fasting.

The fasting day itself was hard – I couldn’t stop thinking about the food I couldn’t eat. I existed on water, cups of tea and fruit over the day. For dinner, I splashed out with eggs on toast. Evenings were definitely the most difficult, particularly when cooking a meal for the family that I couldn’t eat. I was hungry all evening and ended up going to bed early just to get through it. That was the only fasting day I managed to complete.

This eating plan may work for some, but I’m definitely not one of them. With the focus on calories rather than eating more whole less processed foods, I also question the nutritional implications of following this dietary plan.


Intermittent fasting was my least favourite of the three dietary approaches. Yes, it was great being able to resume my normal eating patterns on five days, however, the two fasting days were honestly a struggle. Again, it affected me socially – I had to arrange catch-ups with friends and family dinners around my two fasting days. While this may not sound like a big deal, for me food is a social occasion and I found this approach rather restrictive. Also, it’s a lot of effort estimating and consulting food composition tables to calculate the calorie content of every food item I ate. Some people might think that as a dietitian I should know how many calories or kilojoules are in every single food, however, I don’t and that’s not what dietitians do. I think it’s much more important to look at your diet as a whole, rather than counting calories.

In general

All participants were feeling dietary-fatigue from trying three different eating approaches back-to-back. There wasn’t, therefore, the same level of enthusiasm and passion for trailing this approach. In hindsight, it might have been best to have a ‘washout’ or adjustment period where we were able to revert back to our normal dietary intake before starting a new approach.

It should be noted that the 5:2/intermittent fasting approach is often used for weight loss. With all of the dietitians and nutritionists being of a healthy weight, there was perhaps not the same level of motivation for the team trialling this approach.

How does 5:2 compare to the Heart Foundation’s advice?

In theory, the Heart Foundation’s advice could have much in common with the 5:2 approach, if participants follow a heart-healthy eating pattern. However, it could also lead to inconsistencies with our advice with people opting for foods containing high levels of refined carbohydrates, sugar, salt and/or saturated fat on non-fasting days or nutrient-poor low calorie foods on fasting days. In addition, there is the possibility that the 5:2 approach could lead to followers adopting a ‘restrict-binge’ cycle, where foods may be overeaten and/or poorer food choices made on non-fasting days as a way of countering feelings of deprivation during fasting days.

The Heart Foundation promotes that all foods can be included as part of a healthy diet. Our advice emphasises eating a dietary pattern based largely on minimally-processed foods with plenty of vegetables and fruit. We also recommend including some intact whole grains in place of refined grains: legumes, nuts, seeds, and other sources of healthy fats such as oily fish. Non-processed lean meats or poultry and/or dairy may also be included.

We believe that if people focus on the right foods, and in the right proportions then there is no need to resort to extremes. Ultimately, get the foods right and the calories will take care of themselves.

(Disclaimer: The content in this blog does not represent the views of the Heart Foundation. Instead, it is the views and opinions of Heart Foundation staff who are speaking from personal experience.)

Find out our take on Low Carb High Fat

Here are our experiences on Paleo

Dave Monro, NZRD

Dave Monro, NZRD

Chief Advisor Food and Nutrition

I completed chef training while studying nutrition/ dietetics and enjoy combining both of these elements to develop practical solutions for families to eat healthier.