A common myth is that exercise always equals weight loss. Except it is not always true. Often exercise equals muscle gain, which means weight gain. You might also be losing fat too, but it will be confusing as to how much muscle you are gaining and fat you are losing.
During a strict diet where a person is consuming less calories than their needs but still using the same amount of calories for their daily activities you will see constant weight loss as the body consumes fat stores to make up the difference. (During such a diet it is recommended they eat a fair bit of lean protein and supplement their diet with weightlifting in order to maintain muscle tone.)
During a less strict diet wherein a person doesn't know how many calories they are consuming then they might sometimes be eating more than they actually need and see combinations of weight loss on some days and weight gain on other days.
Note - Remember to weigh yourself in the morning before breakfast to get more accurate results. If you eat a meal, especially a large meal, weight measurements will give you an inaccurate glimpse of your true weight.
Large meals, extra water retention, binge eating are some of the biggest contributors to weight fluctuations, but there are other factors as well such as:
#1. Muscle Gain - Muscle weighs more than fat so even a little muscle gain can result in overall weight gain. This frequently happens when people are exercising, as people often gain muscle faster than they lose fat due to a combination of factors. Learn more by reading How Fast Can You Grow Muscle?
#2. Muscle Loss - It is common for people on fad diets to also lose muscle due to a lack of protein, vitamins and minerals in their diet. This can create a false sense of fat loss because your scales don't know whether you are losing muscle or losing fat. Often people gain the weight back after they quit the diet because their muscle weight can regrow at a faster weight due to muscle memory. See also Two Alternative Models for Predicting Muscle Growth.
Personal Note: I have to this myself often because I store my electronic scale sideways so whenever I plop it on the floor to check my weight I have to first wait for it to recalibrate by stepping on and off it a couple times and then finally getting an accurate reading.
Another possibility is that you have an old set of scales that uses a tension spring to measure weight, and the spring is old and worn out (and losing tension). Best option is to recycle it and buy a new set of scales.
If you have access to an old fashioned scale like the one below then absolutely use it. That is the kind of scale used by doctors because they are the most accurate.
#4. Too Much Salt / Sodium - Eating too much salt / sodium causes your body to retain more water and also more fat. Simply cutting all your salty foods from your diet can cause a sudden shift towards weight loss and fat loss. Eat more veggies and less salty foods and you can see a dramatic change. A constant over abundance of salty foods will cause your body to store more fat on a daily basis.
#5. Constipation - Nothing a quick laxative wouldn't fix. Otherwise try eating more foods that are high in fibre. Having a good bowel movement on a daily basis is definitely a good thing. Try to weigh yourself AFTER you've had a bowel movement and before you eat breakfast.
#6. Hormonal Changes - Women and men both suffer from monthly hormonal changes that can cause their weight to fluctuate. Hormonal levels can even be effected by your mood, as feelings of depression cause various hormones to be released which causes weight gain. In contrast feelings of happiness and contentment cause hormones which induce weight loss.
HANDY TIPS FOR COUNTERING NEGATIVE WEIGHT FLUCTUATIONS
#1. Don't weigh yourself every day. Instead pick a day (eg. Tuesday) and always weigh yourself on that day after your morning bowel movement and before breakfast.
#2. Keep track of your weight fluctuations from week to week by tracking them on a piece of paper that you keep near your scales.
#3. Avoid large meals, parties where you might overeat, binge eating, etc the day before you weigh yourself. Also avoid salty foods, caffeine, nicotine, alcohol, sugary treats and anything else you know is bad for you.
#4. Drink more water to bring your sodium levels down. Water also helps remove contaminants in your system from toxins, as water acts a natural detoxifier. Other natural detoxifiers include lemon juice, green tea, broccoli (although many other vegetables also work wonders), dandelion tea, fresh cranberry juice. Learn more about lowering your toxin levels.
ALTERNATIVES TO WEIGHING YOURSELF
A better way to judge your true weight is to look at how well your clothes fit. If your clothes feel roomier or baggier, then you've lost weight.
If possible try to also get monthly measurements of your body fat. This will give you a percentage of your total weight which is fat and a better idea of whether you are losing or gaining based on the percentage.
Try using fat calipers.
An old fashioned route is to use a tape measure. The tape measure will be less accurate around your middle (as you might gain muscle there if you are doing abdominal exercises) so I recommend also measuring your hips (as your body often stores fat in your buttocks instead) and keeping track of both your waist and hips measurements.
