5 Causes of Daily Weight Fluctuations

daily weight fluctuationsYour weight will never drop consistently when dieting. It will drop 1lb one day, then climb 2lbs the next day.

This leaves may dieters frustrated. They assume they aren’t making progress and abandon or switch diets prematurely.

But weight fluctuations don’t always mean you have gained or lost fat. They can be caused by a whole host of things.

5 Reasons Your Weight Fluctuates Daily

Despite having a good diet and a solid exercise plan in place, there are several reasons why you might be seeing the scale rise and fall on a daily basis.

1. Food volume

Even if you eat the same number of calories from one day to the next, the volume of food changes (because 500 calories worth of spinach does not not weight the same as 500 calories worth of chicken). One day you might eat 2,000 calories of food which weighs a total of 2lbs. The next day you might eat 2,000 calories of food that weighs only 1lb. Therefore, the amount of waste product that sits in your intestines produced by digestion of this food varies daily, affecting your total body weight.

2. Salt

Eat foods with a higher salt content and the next day you will be heavier. Eating salty foods make you thirsty. As a result you drink more water than normal, and your kidneys work to increase the volume of water held in the bloodstream (in order to ensure that the concentration of electrolytes remains constant). The extra water also flows from the bloodstream into other cells (such as skin cells) via the process of osmosis. This leads to ‘puffy’ looking skin – caused because of that extra water in there.

When you decrease your salt intake, the reverse happens. Bodybuilders will eliminate virtually all salt from their diets in the few days before a contest in order to make their skin as flat as possible on the day, revealing the shape of their muscles underneath.

3. Exercise

A bout of intense exercise can also lead to an increase in water retention. Exercise makes you hot causing sweating and the loss of salt. To prevent further dehydration your body releases an anti-diuretic hormone and the hormone aldosterone. Together these hormones help balance your fluid levels and keep saline levels normal. They can, however, can cause the body to overcompensate and hold on to too much salt, which causes 10-15% more water to be retained in your body, leading to a weight increase on the scales.

4. The ‘Whoosh’ Effect

This isn’t really based on scientific fact, but a phenomenon that many people seem to experience. Your body weight stays the same for several days and then…whoosh!…the scales take a massive jump downwards. One explanation is that your body replaces fills shrinking fat cells with water as you lose fat. You are getting leaner, but the extra water trapped in the cells makes you weigh the same on the scales. Then all of a sudden the water is released and you magically drop body weight. Some suggest that a re-feed day or meal can cause this whoosh of water to be released.

5. Cheats meals

10% of the time you should break your diet and eat what you want (within reason – it’s not a license to go cRaZy!). On days following these cheat meals, you can easily gain 2-10 lbs (depending on your starting weight). Again, it is important to understand that this is not all fat. Most of it is due to the factors above. The foods you want to eat at this time are generally the ones higher in salt, plus there is usually an increase in food volume. This extra water weight usually drops off within 2-3 days.

4 Tips On Judging Weight Loss Progress

You should now understand some of the causes of daily weight fluctuations, and that the scale going up does not always mean you have gotten fatter. Here are 4 ways to judge your progress and assess if you really are getting leaner.

1. Weigh yourself weekly, not daily

Don’t weigh yourself every day unless you can handle it psychologically. Better is to jump on the scales weekly, note down your weight, then forget about it until the next time. Every two weeks, look at your historical data to get a good indication of the trend. If you haven’t lost weight compared to your reading 2 weeks before then it’s time to re-think your diet.

2. Avoid cheat meals right before a weigh-in

Eating a cheat meal the night before your weigh-in is going to blow your measurements out of the water. That extra 5-10 lbs of water weight will make it impossible for you to see the wood for the trees. If you DO happen to cheat the night before then subtract the amount of water weight you normally gain when cheating from your figures and use those to asses your progress.

3. Weigh yourself at the same time of day

It goes without saying that you are heavier at night than in the morning. Keep your weigh-in times constant to prevent unnecessary additional variables. I suggest you do them in the morning, after a pee stop, but before breakfast.

4. Use other metrics besides weight

Don’t just rely on body weight. If your clothes are looser and you look better in the mirror, congratulate yourself – even if your weight on the scales has gone up.


Daily weight fluctuations are just a natural part of losing weight. By understanding what causes them you can take a more objective look at your weight before you are tempted to give up.

Instead of worrying about your weight daily, look for a downwards trend every 2 weeks. That is a good amount of time to see progress, without getting caught out by water retention and other variables.

If you don’t see a significant weight loss in that 2 week period then you need to change your diet strategy.

Tags: , , , , ,

About Ryan

I'm Ryan, a 31-year old who constantly struggles with losing fat. I now follow healthy eating strategies and practice stress free living. This blog chronicles my thoughts about fitness, nutrition, exercise, relaxing and staying healthy.

Speak Your Mind


Notify me of followup comments via e-mail. You can also subscribe without commenting.