Does rapid weight loss result in rapid weight gain?

I’m sure we’ve all heard the common misconception that ‘the quicker you lose weight, the quicker it will return,’ or ‘exercise is the only sustainable method of weight loss.’

Rapid weight loss in the first few days of any diet can indeed be quickly regained.   However, the weight rapid weight loss and gain is glycogen, not fat weight.

Another way of describing glycogen is ‘water weight’. You can often feel that you are carrying extra ‘water weight’ by your clothes or rings feeling a little tighter. Maybe your feet, hands and stomach feel a bit bigger than normal.

We have two methods of storing energy in the body, these are as glycogen (‘water weight’) and fat.

Glycogen is formed to store sugar in the body when we consume more calories than we are using. It is a combination of sugar and water in a ratio of 1:3. This means that for every one part of sugar, there are 3 parts of water stored too. This is where the term ‘water weight’ comes from.

Your ‘water weight’ changes throughout the day. You will be at your lightest first thing in the morning when you have passed urine. During the day your water weight goes up and down as you eat and then use up energy.

Other factors also affect your ‘water weight’ and what you weigh on the scales.  These factors are :

The other possible explanation for the misconception about the speed of weight loss and regain stems from the fact that some people who lose weight rapidly think that they can go back to eating and drinking as much as they did before they went on a diet but without regaining weight.  Unfortunately, this cannot happen, they will simply regain all the weight they lost.

After weight loss, your energy usage is reduced as you now have a smaller body which requires less energy (think of the way a smaller car requires less fuel).  If you revert to pre diet habits (lifestyle and eating) then it stands to reason that your weight will return to its pre diet state. After dieting, it is important to calculate your approximate energy usage from your new smaller body, and then eat and shop with this figure in mind.

BMI Calculator/TDEE