Two weeks in

Keeping on track, the weight loss, as expected is above prediction, but this will be mainly water loss. My BF has come down as well and seems to be in line with prediction, though the daily variation causes quite a bit of noise in the measurement as I don't think I've got the measurement protocol settled yet.
With Biometric impedance measurement it's important to measure at the same time each day and under the same conditions as much as possible. Levels of hydration and stomach contents have quite an influence and so measurement can vary by a couple of percentage points through the day. The system is also quite sensitive to weight input and the scales don't have the same discrimination as the BF monitor. Still it's a guide and seems to be giving the right numbers for the Katch McArdle equation.
I've been trying to find out a bit about the expected loss from Body Fat vs Fat Free Mass. Based on composition around 87% of fat tissue is lipids, that is fat from which the body can derive energy, so that's where the 7800K cal/kg (32.2 Mj/kg) estimate is derived from, Lean tissue provides less energy per kg. In most studies a rule of thumb seems to be around 75% - 25% FM vs FFM loss, although this isn't linear. The linked article develops this from the Forbes equation and shows that as BF percentage decreases the amount of energy derived from FFM increases considerably. The result is that the fatter you are initially the large deficit you'll need to lose weight. Doesn't seem fair does it?
However the body has other mechanisms and for lean individuals the starvation mode seems to kick in quickly, probably something to do with the hormones released into the blood stream as certain tissues are used for energy. The role of Leptin in this mechanism is probably one of the keys, but there are probably other hormones involved.
The important point for me is that the mechanisms are complex so expectation and prediction are complex. The body isn't a simple machine as it seems to adapt it's efficiency depending on the source of fuel, so in this case a calorie isn't a calorie making all the general advice of 500Kcal per day to lose one pound per week a bit too general.
If my estimates are right then I should be around 1.2kg per week at the moment, but then that's also within the range of my daily variation depending on food intake and hydration so measurement protocol matters. Repeated conditions, same time of day, equivalent activity, equivalent eating and drinking patterns. The what do you weigh question should come with a standard deviation attached!

New Beginings

Just over a year ago I managed to lose 25Kg or so, and for the last year have maintained that, losing a bit and gaining a bit, but generally keeping it under control. This has been a challenge as in the past my weight loss hasn't stuck.

I’ve now decided to take the next step and tackle the rest. The plan is to get down to Body Fat percentage below 20, and preferably under 15. This should also give me a BMI of less than 25.

I’m using a Omron Body fat monitor (http://www.omron-healthcare.com/en/product/weight_management/HBF-306-E.html) although mine’s an older model with a slightly different algorithm in it I think. These Biometric Impedance devices have problems as they are sensitive to hydration but a bit like weighing yourself it’s about consistency and taking it as a good guide. Roughly right rather than precisely wrong!

The scales are a set of EKS mechanical scales (http://www.eks-int.com/index.php?id=111). These seem to have good repeatability and consistency over measurements.

The prediction is based on using the Katch Mcardle formulae (http://en.wikipedia.org/wiki/Basal_metabolic_rate) and also taking into account the maximum deficit that my body can take before starting to lose Fat Free mass (see Alpert SS. A limit on the energy transfer rate from the human fat store in hypophagia. J Theor Biol. 2005 Mar 7;233(1):1-13.

The exercise is a mix of Cardio, interval training on an elliptical trainer for 60 minutes a session plus weight training. The mix will change over time with quite a lot of CV at the beginning and more weights towards the end.

The purpose of this blog is to track progress and to share some of what I learn.