Friday, 2 January 2009

Why counting Calories and weighing yourself regularly can be a waste of time.

To lose weight, eat fewer Calories than you burn. Sounds fairly straightforward, doesn't it?

What is a Calorie?

One dietary Calorie (Cal) is 1000calories, or 1kcal for short. A calorie (cal) is the amount of energy required to heat 1g (1mL) of water by 1degree C. As 1cal is a tiny amount of energy, kcal is commonly used. I prefer to use kcal rather than Cal, as the first word in a sentence is always capitalised which could cause confusion.

The SI unit of energy is the Joule (J) and is the amount of energy required to lift a 1kg weight 1m into the air. As 1J is also a tiny amount of energy, kJ is commonly used. There are 4.186kJ in 1kcal.

Why counting Calories can be a waste of time.

1. When the label on a packet of food states that the food contains Xkcals or YkJ, the number may be inaccurate. See Food Composition Analysis and its Implications for Dietary Planning.

2. Many people are hopeless at judging portion sizes, even when using measuring spoons! Watch the following video made by Leigh Peele called Fat Loss Tips! Shocking!

3. People suffer from "The dieter's Paradox", where they erroneously believe that adding something supposedly healthy to Crap-In-A-Bag/Box/Bottle (CIAB) reduces the total number of calories. See The Dieter’s Paradox – Research Review.

4. If people reach their Calorie intake target for the whole day, but it's only 5pm and they're starving hungry, they're going to eat more food and exceed their target, unless they have supreme willpower. If you're eating the wrong diet, Calorie targets are moot. Find a diet where Calorie intake is naturally reduced, without causing hunger pangs.

Why weighing yourself regularly can be a waste of time.

As mentioned previously, scales cannot distinguish between muscle, body-fat, glycogen+water, urine, faeces etc. Bodyweight can fluctuate considerably on a day-to-day basis. The following list (source forgotten!) lists the effect of various things on body-weight.

Thing________________________Weight change (lb)
Glycogen supercompensation________~+10
Glycogen replenishment/depletion_+/-4 to 5
Pre-menstrual water retention_____~+5
Eating a high-sodium meal__________+2 to 3
Fluid retention on airplane flight +2 to 3
Going to the loo (No.2)____________-1 to 2
Going to the loo (No.1)___________~-0.5
Drinking a mug of tea_____________~+0.5

So step away from the scales. There's nothing to see here, folks! If your belt/clothes are getting tighter, reduce the frequency of eating "treats" (moreish foods that are usually high in sugar, fat, salt & flavourings).

And finally, a little light relief. If I just waffle on about Diet & Nutrition all the time, it can get boring. So here's a YouTube video of a really cool cat that must have watched the Doctor Who episode "Blink". You know, the one with the Weeping Angels. Ninja cat comes closer while not moving!


Adam said...

I knew changes in weight are volatile but I was never aware that Glycogen supercompensation could cause that volatile of a fluctuation in weight gain.

I also do think people who are dieting may experience periods of coritsol related water-retention as shown in starvation experiments. I imagine post-break up, a stressful week of work, etc could also cause weight gain. Such factors just further your point: Weighing yourself is pretty damn useless!

Nigel Kinbrum said...

Normally, I say where I get my information from, but I didn't on this occasion. I wrote this post such a long time ago that I can't remember where I got the figures from! I think that they're from one of my books on nutrition.

But yeah. Day-to-day weighing is useless. Taking a 7-day rolling average is a bit better. When a long period of stress that's beyond your control comes to an end, the resulting "whoosh" is amazing.

Ballomar Cingetorigis said...

When you weigh yourself, the more data points you have the better. Should be obvious to a science guy.

Nigel Kinbrum said...

Unfortunately, most people who step on scales aren't science guys or gals. They're Joe & Josephine public who go "OMG! I've put on a couple of pounds today. Gotta go on a diet." :-/

Ballomar Cingetorigis said...

The answer is education. Obviously Excel and a moving average are all you need .

Nigel Kinbrum said...

I use a very low-tech method. I keep my belt on the same hole. If it gets tighter, I cut down on my food intake a bit.

Ballomar Cingetorigis said...

I see what you did there.