I didn’t diet before age 26, in part because of the huge number of faddy, commercial diets. They make weight loss seem like alchemy, as though you can’t work any of this stuff out on your own. Even big players in this industry make me extremely angry doing things like labelling food as “si[y]nful”, or picking one macronutrient and pretending that it’s bad for you. This is nonsense, but it serves to keep the diet industry going, with customers who cycle through weight gain and loss throwing money at the latest diet each time they feel bad about their weight.

I’ve got friends and family who have had success with those diets, and I’m pleased for them, but weight loss is so simple that no system beyond calorie counting and tracking should be needed. Anyone can work out how much they should eat for free, using well researched formulae to figure out their requirements, and with the comprehensive databases of food nutritional data available online, counting how much you’ve eaten is easy too. By spending half an hour getting to understand the basics, you can start to build a better relationship with food, and learn how much you can eat, not what you should or shouldn’t eat. Everyone likes cake, so let’s not take it away from ourselves!


I’m going to go through the figures, because it was really helpful to me. If you feel like you’re glazing over with this, there are many, many calculators available to give you the answer quickly. I didn’t really like any of them, so I’m probably going to write one as a little programming project, but you’ll find one easily enough.

My numbers

My goal is to lose around a kilogram per week for around six months, to get down to 78kg by my thirtieth birthday in September. I’m half way there, in both time and weight loss. After I set my goal weight, I worked out what my daily calorie intake should be to achieve it.

Calorie calculations can get a bit handwavy, particularly when it comes to activity level, but central to them all is the calculation of your BMR (Basal Metabolic Rate), the number of calories you burn in a totally resting state. I used the Mifflin St. Jeor equation to calculate mine, which is currently 1835 kcal per day.

10 x weight(kg) + 6.25 x height(cm) - 5 x age(years) + S

(S is +5 for male, -161 for female)

868 + 1106.25 - 145 + 5 = 1834.25

Using that BMR, I calculated my actual calorie burn, adjusted for activity level as per this chart:

  1. Sedentry - BMR x 1.2
  2. Lightly active - BMR x 1.375
  3. Moderately active - BMR x 1.55
  4. Very active - BMR x 1.725
  5. Extremely active - BMR x 1.9

The activity level of many people who work in offices is in the sedentry category, but since I’ve been tracking my step count and keeping it above 10,000 steps per day, I opted for lightly active. This gives me a total calorie burn of 2520 kcal/day.

Actually losing weight

2520kcal is what I’d need to eat to maintain my current weight, whereas I want my intake geared for losing 1kg/week. 1kg of weight loss takes a 7000 kcal deficit, so it’s a simple case of subtracting 1000 kcal per day, leaving me with 1520 kcal to eat each day.

When I started, I was heavier, so my goal was 1600 kcal/day. I’ve kept to that so far, as it’s a little demoralising to have the calories I can eat go down and down, and I find it makes it harder to stick to a food routine. Once I get to my goal weight, the number of calories I can eat will increase significantly, so I don’t need to get used to that severely restricted diet long term to maintain my weight. I closely track my weight, and if I find that I’m losing less than 1kg per week I’ll revisit that, but currently I have the opposite problem, so reducing my intake further would seem like a bad plan!

I’m doing other exercise which I track separately, though I currently try not to eat the calories which I log as burned from that exercise as it’s so difficult to get an accurate measurement, and I don’t want to form a habit of eating as a reward for the exercise I should just be doing as normal.