How often should you weigh yourself?
Many sensible people think that we should only weigh ourselves about once a week. There are three main reasons for this.
- Scales are not totally accurate, so if you measure just small changes in body weight, it might just be scale error. (I think this is an old fashioned argument. Modern digital scales can reliably measure to within 100gm, which is all you need).
- If you are weighing yourself all the time and obsessing about your weight you will probably fail. This is true. Weight loss is a long-term journey, and a period of less than a week does not make much difference to that total journey. You should think long term, not day-to-day.
- Your body weight fluctuates quite a lot from day to day. We can go up or down one kilo with no change in body fat; just changes in the retention of food and fluid. This is true, so let’s understand it.
However, I would argue that when you first start your weight loss program there can be some benefit in weighing yourself not just several times a week, but in fact several times a day. The reason to do this is not to obsess about your weight but to reassure yourself that you do fluctuate in weight and that you should not be demotivated by many of the times your body weight goes up.
Let me explain.
The biggest part of losing weight is your attitude. If you are feeling strongly motivated to lose weight you can withstand the internal pressure to eat surprisingly well. But if you are demotivated you can eat a days worth of calories in two minutes.
So managing your own thoughts is very fundamental to losing weight. You need to learn to keep yourself motivated.
The bathroom scale is a great tool for motivation. When you hop on the scale and see that you have lost 1.5 kilos in the last week, you feel really good and you want to do it again, but when you find you have gained one kilo you feel awful, and of course your own thoughts don’t help. One bad weigh-in can completely undermine your confidence in yourself and your weight loss program. One bad weigh-in can confirm that you are weak, that you are useless, that losing weight is impossible and that it’s not worth trying. Of course none of that is true, but it is what your mind tells you.
So how can you use the scale to motivate yourself when you lose weight, but not demotivate yourself when you gain weight?
Answer. For a period of one week, weigh yourself several times a day until you understand the events in your normal day that determine the hour-by-hour fluctuations in your body weight. Once you understand these fluctuations you will be able to separate body fat reduction from short-term fluctuations and understand the actions that lead to a reduction in body fat. After that you can go back to weekly weigh-ins or whatever you feel is appropriate, because you will understand how to lose weight.
What events make your body fluctuate in weight?
The following table contains a list of the main events in your daily life that lead to a gain or loss of weight on the scales. There may be a few more in your life, that are specific to you, so think them through.
|Weight Gain||Weight Loss||Comment|
|Eating food||Emptying your bowel||A lot less comes out than goes in and the amount of weight you carry in your digestive system varies substantially from day to day. The rest leaves your body predominantly via your lungs and your breath, and via your skin.|
|Drinking liquids||Urinating||A litre of water weighs 1kg. Drink a litre of water and your weight goes up 1kg. Urinate a litre of urine and you weight goes down by 1kg.|
|Above average fluid retention||Below average fluid retention||Menstrual cycles, flying, hot weather, and illnesses may all cause your body to retain more fluids than normal. And of course the opposite of each of these may cause a drop in fluid retention, and hence a drop in weight. Although the level of fluid retention will vary from day-to-day, over time it will average out.|
|Doing nothing||70% of the energy you burn up occurs when you are just doing nothing, be that awake or asleep. Weigh yourself before you go to bed and again in the morning and you weigh less. The weight has left your body, predominantly in the form of vapour from your breath.|
|Exercise||I know that a good run, bike ride or gym workout reduces my body weight, despite my attempts to keep it topped up with water. I can lose up to one kg on a long bike ride. It goes, both by sweating and through my breathing.|
So, what I am suggesting you do is buy yourself a set of very reliable scales. Get good digital scales that claim to weigh accurately to within 100gm.
Now weigh yourself before and after all of the main events in your day that impact your body weight.
- Weigh yourself before and after each meal and see how much weight you put on
- Weigh yourself after each drink. Believe me, 200ml of liquid does weigh 200g but it’s great to see it on the scales
- Weigh yourself before and after each “toilet event” (gross I know, no need to tell others you are doing it), and see how much you lose
- Weigh yourself before and after sleeping at night
- Weigh yourself before and after any exercise event
The reason for doing this is not to be obsessive, but to understand the very simple fact that these events do drive your body weight up and down quite substantially. Over time you learn to understand what the scale is telling you. And over time the message becomes quite clear. Your body weight can only go up by putting in food sources (liquid or solid). Everything other than this results in a body weight loss, so you need to be careful with what you put in.
Now clearly digestion and nutrient absorption is a complex biological process and a 500g meal does not result in a 500g weight gain in the medium term, (thank goodness), but there is a very direct relationship between eating food and gaining weight.
My experience of event based weigh-ins
- It’s really exciting that I lose weight when I sleep during the night. It’s a great feeling to do nothing and just have it fall off. I find it motivating.
- I have started drinking water and zero calorie drinks, and black coffee and tea rather than any drink with calories. When I drink 300ml of water I know for a fact that none of it contributes to weight gain. I will lose all of it again, somehow, probably just by breathing. It’s like a bonus. I get all this water, and the weight gain is guaranteed to be temporary. I never worry about a weight gain from drinking water. I can go up 500gm through drinking water and I don’t care in the least! I do not find it demotivating.
- I am a bit surprised at how much weight I lose from exercise. I know it’s mainly just fluid, but it’s still a loss, and even when I put it back in with water (with no calories) I still know my exercise is definitely a net loss. I find it motivating.
- The whole toilet thing is a bit yucky to discuss other than to comment on how much it varies. A big toilet event (yuk sorry) can weigh over 500g, but they vary a lot. It certainly makes me realise what a big impact the timing of toilet habits can have on the whole idea of a weekly weigh-in. This is also often where I often hit a new PB. (sorry again, but keep reading and I’ll explain). I find the loss motivating.
- I fly on planes quite a lot and one hour on a plane can result in the retention of up to a kilo to me, and it can hang around for two to three days. I know this is what happens and I know I lose it again. I do not find this demotivating.
- But my biggest finding is just so obvious. My weight goes up when I eat food. Over the course of a few days if I eat less food it goes up less and if I eat more food it goes up more, and if I eat good food it goes up less and if I eat bad food it goes up more. So obvious, but how does this all help me?
Well, this is where the idea of the PB (personal best) comes in. What happens with my regular “event based” multi-day weigh-ins is that I have far more occasions when my weigh goes down, than when it goes up. I start having many good scale experiences. And because I like these scale experiences I am definitely more careful with what I eat and how much I eat. The result is that I’m losing weight. And now I have more PB’s. With my new focus I have a new lowest weight (PB) about 4 or 5 days out of each week. Instead of waiting for a week for one weigh-in that might go up or down, almost every other day I have a new low point. It might only be 100g below yesterday, but that’s fine. I graph my low point every day (or rather my amazing phone app does) and I enjoy the downward slope of the line. Just ask my friends. I am driving them crazy with the graph on my iPhone.
And when I have a day when it goes up, I always know why and when it went up. If it’s about water, toilet timing, or something I know isn’t body fat related, I don’t mind at all. I understand it and I don’t find it in any way discouraging. But if it is because I have eaten badly I always know, but I’m also very confident I can fix it over the next few days. I just reduce my calories the next day and I’m back on the downward slope.
So it is possible to use your weigh-ins to motivate you and not to demotivate you. An “understandable” weight gain, e.g. water drinking, is no longer demotivating. I get several new low points a week, instead of one and I find this very motivating. And when my weight goes up because I have eaten several bad meals this now feels controllable. It’s not like my body randomly trying to demotivate me but something I respond to very quickly and pull back into line.
So get yourself a good set of digital scales and give it a go for one week. Don’t make it an obsession. Just make it an education.