Why Do You Weigh Less in the Morning

Where I can, I always try to weigh my clients in the morning. There are a couple of reasons for this. Number one, you get a good, consistent reading. Number two, you generally weigh less in the mornings, and, as an act of generosity and a way to motivate them, I like my clients to see things in the best possible light!

But why is this? Why would a morning weigh in be both more reliable and more flattering?

Why do you weigh less in the morning?


The main answer is dehydration. Overnight, you dehydrate as your body continues its normal functions, plus recovering from the fatigue imposed on it the day before, all without taking in any liquid for a good 6-9 hours, depending on how long you typically sleep.

One cup of water weighs approximately half a kilogram. Even slight water retention can cause you to put on serious weight, therefore (this is the reason behind creatine’s well-document ability to suddenly make you gain weight in a matter of days – it makes your muscles retain more water).

If you drink plenty before bed – which can be a very good idea – you will notice that you probably both have more energy in the morning (plus a fuller bladder, unless you got up for that 2 AM bathroom visit) and that your weight fluctuation will be less drastic. Your morning weight loss will be decreased, though your overall body fat levels will remain the same.

In addition to dehydration, you will also have gone at least 6-9 hours without eating – midnight feasts aside. Your body will burn any food you took in before bed as it repairs itself. This means that you will literally be emptier – basic bodily functions will have depleted you of the food mass you were carrying when you went to bed.



These also make morning weigh ins more reliable. If I weigh a client at 7 pm and see they have put on a pound since last week, this isn’t particularly enlightening. They could have had a large lunch. They could have eaten any number of foods that make them retain water. They could simply have drunk more that day than normal. Even the weather can make a difference, with hotter weather making people sweat more.

In the morning, I know they will be as close to a neutral, universally comparable weight as possible. I will be getting a far firmer reading of their lean body mass sans any mixed up variables by weighing them first thing.

As a side note, it’s a good idea to weigh yourself naked (or as close as possible). Of course, I have never weighed a client naked. For starters, the scales are in the middle of the gym, not in the changing room, so that could get awkward. However, if you’re weighing yourself at home, strip down fully. Clothing is as much a variable as anything else – if we’re looking to cut the variables out, this is an easy one to do.

If you can’t strip down, at least empty your pockets and take your shoes off. You don’t want your smart phone and a pair of heavy trainers skewing your results.

Weighing Less and True Weight Loss

Weighing Less and True Weight Loss

This conversation is a good example of why we need to measure more than simple weight when looking to lose weight. This is because most people aren’t actually looking to ‘lose weight’. Few of us care how heavy we are. We care about body fat and use weight as a rough and ready stand in for it.

If you weigh yourself in the morning and see that you’re lighter than the day before, please realise that you haven’t lost body fat. Dehydration is all that’s going on, and you will regain that lost weight by lunchtime as you eat and drink.

This also underlies how silly it is to wonder about the best time of day to take a reading. Realistically, there isn’t one. I like to do it in the mornings, but I often don’t. Clients work with me all day long. I often see them in the evenings, after a full day’s nutrient intake. That’s fine. The main thing is consistency. If they eat and drink consistently, and have regular bathroom visits throughout the day, and I weigh them at the same time every day, variables will still be low enough to give us a good working idea of their weight loss.

Pick a time of day that suits you. Pick a day (I always weigh people on the same day week after week if I can). Stick to this and live a routine-based life and your weigh ins should be demonstrative enough for you to be getting on with.

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Mike Julom, ACE CPT

Mike is an ACE Certified PT and a CrossFit Level 1 Trainer. He is an avid lover of all sports. Basketball, tennis, athletics, volleyball, soccer, squash, golf, table tennis, even darts, you name it! He's a very active CrossFit athlete and has been WOD'ing for over 7 years. With such an intense fitness regime, Mike has learned to take care of his body physically, nutritionally, and spiritually. Mike founded ThisIsWhyImFit as a way to share his vast knowledge of exercises, diets, and general fitness advice.

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