It’s day 9 of my challenge to lose 20kg by Christmas Day. That’s 20% of my bodyweight, no mean feat.
Last year, I used a popular website to motivate myself to lose weight. It involved staking money on yourself to hit a weight loss target. Loads of people join the same challenge and if you don’t make it, you lose your stake. Those who complete the challenge get a share of the losers’ money. Those challenges included losing a maximum of 6% of your weight in 3 months.
So hopefully that put into perspective the size of this challenge.
Why 80kg? Because that matches the weight I reached last Christmas, and it is approaching a healthy weight for me. I should really be in the mid-70s.
The numbers
There are 15 and a bit weeks to go, and I have 16.5kg to lose. So that’s just over a kilo to lose every week. I’ve already lost 3.5kg in just over a week, thankfully, and I think i’ll continue to drop quite quickly for the first few weeks, so hopefully that’ll level out to a kilo per week or below.
There’s an accepted stat that each pound of fat is worth about 3500kcal, so if we go imperial for a minute we can see that I have 36.4lb to lose, meaning I need to achieve a whopping 127, 400kcal deficit. That’s a deficit of 1191kcal PER DAY from here on out.
I’m also not accounting for the possibility that increasing exercise will increase my lean mass, thus boosting my weight. So i’m probably looking at a deficit of 1200kcal/day for over 100 days.
The more I work this out, the more daunting it seems. But I do enjoy a challenge….

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How can I possibly do this?
First off, I hate calorie counting. It’s a pain in the backside to do, and fraught with inaccuracy. Two people can eat the same sized potato and get totally different levels of calories from it. That’s because of two things, food providing variable amounts of nutrition, and people taking different levels of nutrition from the same food.
You also have to factor in that, as you lose weight, you require fewer calories to move around, and as you gain muscle you burn more calories in everything you do. It’s a minefield, and not something you can hope to accurately work out, outside of a lab setting.
So I stick to some simple principles, which fasting really helps me to do.
I start with a period of intermittent fasting to help me get into the swing of feeling hungry, skipping meals and getting my activity levels up. I then go into a period of OMAD (one meal a day) and multi-day fasting. OMAD becomes my baseline, and multi-day fasting is where I step things up.
I also prefer to look at the scales instead of trying to calculate what i’m eating. I will look at food labels to get a rough idea of my caloric intake, but this is with a view to deciding which foods are calorie dense, or otherwise, and thus which ones I ought to avoid. The scales tell me if i’m doing the right thing, and if not, I can investigate why. It’s also important to know what my targets need to be.
My Omron scales estimate that I require a shade under 2000kcal to maintain my weight. That’s one benefit of starting heavy – the weight will fall off quickly to begin with. My Garmin watch tells me that a typical hour walk around my hilly local route burns 430kcal (again, who knows how accurate this is?).
It can be easier to take exercise out of the equation, and see it as bonus calorie burn. This is easier with OMAD. When you do OMAD, you only have one meal to thing about, obviously. So if you have a rough idea that you’re eating 1000 calories in that one meal (meaning you can fit quite a lot of food in), you’re already onto a 1000kcal deficit for that day, even if you sit on your backside all day. Throw in a walk and i’ve exceeded my caloric deficit target for the day.
And that’s why I like it. It’s incredibly powerful and it allows you to enjoy an awesome meal – which, let me tell you, is going to taste incredible.
When I get on to longer periods of fasting, i’ll literally be burning 2000kcal of fat every day without trying.
Or, I could walk for four hours a day, or run, row and cycle for hours a day (other exercises are available). I don’t have the spare hours to play with, even if i was physically capable of those feats.

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There are loads of fasting and intermittent fasting routines out there. The 5:2 diet, 16:8, the warrior diet, alternate day fasting etc etc. For me, this is what works best, but you might find something works better for you. If you feel awful on OMAD, don’t do it. 5:2 might suit you better. Some people actually really enjoy 72h fasts, some find 48h is easy and anything beyond that is too hard. I’ve chosen the method that I think will be possible and will help me hit my target.
Jason Fung’s book has loads of ideas (Amazon affiliate link here). You might also have a really active lifestyle and love hitting the gym, in which case you probably don’t need to be reading this blog.
In a future post, i’ll get into some practical pointers for doing OMAD. I’m currently 22 hours into a fast and looking forward to today’s meal. Thanks for reading and take care of yourself.
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