Fitness Friday – Trying The 5/2 Diet

~700 words, ~3 min reading time

So, I’m in the midst of a “cut”, and I’m trying a new technique: the 5/2 diet. Let me compare it with what I’ve done in the past.

Previously, I followed the Kinobody cutting diet. So, five days per week, I’d eat in a calorie deficit, and two days per week, I’d eat at a slight surplus. After some experimenting, I’ve found that 1600 calories on my low-calorie days and 2500 on my high-calorie days was about right to hit my weight loss goals. This approach basically has “diet breaks” built in on those two high-calorie days per week, and diet breaks have been shown to have positive effects on things like maintaining lean body mass and metabolism. Greg O’Gallagher at Kinobody also suggests taking explicit diet breaks whenever weight-loss stalls.

The 5/2 diet, though, reverses things. Rather than five days of deficit and two days of surplus, you eat five days at maintenance and two days at a very sharp deficit. After doing the calculations, that means I’m eating 2300 calories per day five days per week, and 800 calories per day two days per week. Yes, 800 calories is VERY little – but it is fairly easy to hit simply by fasting for most of the day, and just eating a reasonable dinner. (Note: the original Fast Diet – which the 5/2 diet comes from – says to eat “normally” – that is, don’t bother tracking – for 5 days, and to eat 500-600 calories for two days of the week. I’m following the modified version that I linked above.)

In terms of weekly calorie intake, the two diets are very similar. 1600×5 + 2500×2 = 13,000 calories per week. 2300×5 + 800×2 = 13,100.

The big difference is in the eating pattern. For me, the 5/2 diet has been significantly easier, because I don’t feel like I have to track quite as closely. On maintenance days, I keep track of what I eat, try not to go overboard, and then make sure I hit fairly close to my calories by adjusting my evening snacks after the kids are in bed. In contrast, during my 5 low-calorie days per week under my previous diet scheme, I had to pay a lot more attention to what I was eating each meal to make sure that I was (1) not using up too many of my calories, but also (2) hitting protein goals along the way. That was a lot of attention having to be paid to what I was eating. The 5/2 diet reduces that significantly.

Another big benefit that I’ve found for the 5/2 diet is that I can keep doing it – or something close to it – even when I’m traveling. On my previous diet, I would simply abandon the diet if I went on a trip, simply because it’s too hard to control food intake. I figured 7 days wouldn’t do any permanent damage – and this is correct, as far as that goes. But, it does set you back a bit. But, I’m out of town this week for a seminar – and I’m mostly sticking to the 5/2 diet despite that, even though I’m not tracking calories exactly. 5 days, I’m eating “normally” more or less (so, probably near, but slightly above maintenance, I would guess), and two days, I’m just eating dinner and maybe a smaller snack. In any case, not eating until dinner time basically ensures that I won’t be eating maintenance-level calories those days. So, while I may lose some ground from not tracking calories precisely, I don’t expect I’ll lose much ground – and that’s something.

One downside, though: I am definitely hungry on my 800 calories days – where I hadn’t really experienced that as much on the 1600/2500 split. But, it’s not that big a deal. Drinking lots of water helps, and you do get used to it on some level. Plus, it’s just one day – then I know I get a couple days eating normally.

Naturally, there are some people who absolutely should not do this – it’s particularly dangerous for diabetics. Children and pregnant or nursing mothers should also do something else, most likely. But, it seems to be going okay for me so far – sadly, it’s too early to report results.

1 thought on “Fitness Friday – Trying The 5/2 Diet”

  1. Looking forward to hearing results. I have been doing 20:4 for about a month, with a relaxed eating window on Saturday and Sunday. It is remarkably easy because I’m not counting anything, though I am generally trying to avoid refined sugars and lots of carbs. I think I’ve trained myself to not feel hungry until it is time to eat, too. Yesterday, I didn’t eat until about an hour and a half into my usual eating window with no trouble.

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