As noted in my earlier post, I've been losing weight this year.

Results

In particular, to give some numbers here, this is how my weight has changed over the course of this year:

• 16/01/11 - 117.1 kg
• 13/02/11 - 113 kg
• 13/03/11 - 110.9 kg
• 17/04/11 - 109 kg
• 15/05/11 - 107.4 kg
• 12/06/11 - 105.7 kg
• 17/07/11 - 101.2 kg
• 14/08/11 - 98.9 kg
• 18/09/11 - 99.3 kg
• 16/10/11 - 98.2 kg
• 13/11/11 - 95.6 kg
• 11/12/11 - 93.9 kg

So, clearly, it's working :-)

Method

In summary I've done this by:

• Keeping a detailed food diary - using rednotebook. I've used it to count calories. The purpose behind this was self-education about how many calories different foods really contain.
• Calculating my RDA once per week using this formula
  Calories = ( 10 * weight in kg + 6.25 * height in cm - 5 * age + 5 ) * activity factor
  (The formula for women is - (10 * weight in kg + 6.25 * height in cm- 5 * age - 161) * activity factor )
  Note this takes into account activity levels. Fat people (like me) tend to have a very low activity factor. ("I have a low metabolism" is usually asserted without it being tested, and often wrong).
• Aiming to eat about 75% of RDA per day, at most, but not worried too much if I go over that once or twice a week, and taken care to go over 85% as little as possible and not go under 60% as much as possible.
• Measuring the weights of food I have no idea of their weights to calculate RDA, used smaller plates, and bowls that hold known, more sensible, portion sizes.
• Snacking primarily on protein rich/calcium rich/low fat foods to control hunger/snacking urges. (babybel light primarily)

All of this is explained in detail in the earlier post.

Crucially, two things I have not done:

• I have not particularly changed my exercise levels. I walk to/from the station, and cycle occasionally in good weather in summer. I do have much more energy now though. Or rather I probably have the same amount of energy, but more is available for things other than shifting my weight around.
• I have also not denied myself foods. Yes, I've had cake, pizza, chips etc. I've just learnt what a sensible portion size looks like.

Observations

Based on this, I've got sufficient data - 47 weeks' data - to create a heatmap / scattergraph based on:

• Amount of calories "over" eaten per week relative to RDA - -25% means 75% of calories eaten. I've picked "over eaten", because it puts RDA down the middle of the graph. These are not daily averages, these are relative to the weekly calorie allowance.
• Amount of weight gained

Which enables me to examine the reasonable hypothesis - does eating more that RDA correlate with weight gain, and under eating correlate with weight loss ?

Well, the graph below is based on those 47 weeks' data.

To me, what that says is pretty clearly - yes, over eating relative to RDA does correlate with weight gain, and undereating RDA does tend to correlate with weight loss.

Looking closer, if you over eat over RDA, there are 6 data points all showng weight gain. If you look at the 85% point, there are 5 datapoints which relate to weight loss, and 7 that relate to weight gain, and between 85% and 100% being 1 with gain and 5 with loss. Below 85% there is 1 datapoint with weight gain and 34 with weight gain.

Some tentative conclusions

Whilst correlation does not imply causation, let's presume it's a reasonable conclusion.

If that's the case, this means we can derive some guiding principles from this, ordered by how useful I think they are:

• Weeks where you eat consistently less than 85% of RDA will result in weightloss.
• If you're feasting (eg christmas, easter), then feast, then stop. The worst thing you can do is (for example) feast solidly for 2-3 weeks in a row. The alternative is to replace the usual foods you would eat with the christmassy foods if you just want to eat christmassy foods over an extended period.
• It's the long term (week/fortnight) RDA calorie count that matters.
• Short term (2-3 day) calorie restriction (eg "detox diets") or calorie binges (eg family birthday party weekend) may have a short term effect, but no long term positive/negative effect.
• There's no apparent benefit of going below 70% of RDA.
• Weeks exceeding total RDA for the week will result in weight gain.
• Working on a weekly calorie budget is easier/less restrictive than a daily denial based allowance.
• Weeks with weight gain, will gain about a pound or two (0.5-1kg)
• Weeks with weight loss, will lose about a pound or two (0.5-1kg, average 0.7kg)
• If you've piled on weight, day in day out, for 2 years, it will take you 2 years to lose it.

I'm not claiming that these conclusions apply to others, but based on the numbers, I do think that they apply to me.

Slightly Silly, But Nice Observation

There's one final point, according to RDA I "should" have eaten 792,235 calories. I've actually eaten 638,000 calories (about 80% overall), and lost 23.2kg. That's 154235 calories, or 6648 calories per kilo. That's about the same amount of calories as in a kilo of sunflower margarine. There's makes a rather nice parallel.

So, under eat by a tub of margarine, and lose a tub of margarine-worth of weight. Very literal, and very true.

What do you call this diet then

I've been asked by a few people what diet I'm doing. I think I call it the "putting less in one end than comes out the other diet". Bit gross but pretty accurate :-)

That or just "I'm doing the eating less / not stuffing my face diet".

Does also mean I can just enjoy food, as long as I make it count. But that's pretty fun, 'cos food is fun :-)