Initial diet & water weight loss - question

helaurin

Hi,

I'm told that generally when a person starts a diet, that at first, all they lose is "water weight" - not actual fat, etc.

How much of that initial loss is really water weight? Is it a general percentage of the person's starting weight? Or is it the weight that the person first loses over a certain number of days at the start of the diet?

For example - I started at about 187 pounds, and in the past 11/12 days, I've dropped 9 pounds. I've also been averaging about 1,350 calories intake per day, and have been hitting at least 7,228 steps each day (some days more) - that's a big increase in activity level for me.

Was ALL of that just water weight, and does that mean I haven't actually lost any actual fat?

I've heard various claims (the first 5% is water, the first 14 days is water, even the first month is water) etc.

What's the scoop?

kimny72

There's really no way to tell. Generally unless you are obese, or alternatively lean, you can typically lose 0.5lbs-2 lbs of fat per week.

But it really doesn't matter Weight loss is a long journey, and what's important is the trend over weeks and months. As you are trending down, you will occasionally have weeks where you don't lose anything or even gain a bit. Caught up in there will be water weight swings in both directions. Look long term, don't sweat the short term stuff!

sijomial

I'm told that generally when a person starts a diet, that at first, all they lose is "water weight" - not actual fat, etc.
Wrong, not all, some and that's variable across different people and different eating styles - if you are in a calorie deficit that deficit is being made up from your body's energy stores.
If as part of your new diet your food volume is also down you also have less food weight in your gut.

How much of that initial loss is really water weight?
No real way to know for sure but your could back calculate your calorie deficit and take that as your fat loss but that's making a big assumption your logging is accurate. Also if you switch to low carb you may run down your glycogen stores somewhat.

For example - I started at about 187 pounds, and in the past 11/12 days, I've dropped 9 pounds. I've also been averaging about 1,350 calories intake per day.
For a rough guess working out your average TDEE over that 11 or 12 days and subtract your 1350 average to estimate your actual deficit. Note estimate!

Was ALL of that just water weight, and does that mean I haven't actually lost any actual fat?
No not all.

I've heard various claims (the first 5% is water, the first 14 days is water, even the first month is water) etc.
Sounds rather silly to make claims that everyone would be the same, sounds completely stupid for people to claim ALL the weight is water so would advise ignoring whatever source you got that from - can someone magically make energy out of nothing? Of course not, that energy has to come from somewhere.

What's the scoop?
Fast weight loss (and gain) out of line with calorie deficit is highly likely to be water related and have many causes.
Does it actually matter? It makes it harder to judge your fat loss so the first couple of weeks data is poor. Will that matter in a month or two months time when your real weight loss trend starts to become apparent?

HeidiCooksSupper

I attribute much of this to the switch to a low-sodium diet. Many checkout counter magazine diets that promise huge weight loss in just a week assume they are switching folks from a high-sodium diet of processed foods to a low-sodium diet of fresh foods and veggies.

briscogun

Well, if you've lost 9 lbs in 12 days, if it were all fat then you'd have to have been eating at a daily deficit of 2,625 calories. So there was probably an amount of water weight in there.

So when I first started my most recent weight loss a few months back, I had gone out on a Sunday to the bar & grill then started my diet Monday. Weighed on Monday for a starting weight. Tuesday I was 3 lbs lighter. I did not eat at a 10,000 calorie deficit on Monday. It was a combination of sodium from Sunday, water weight, carbs, etc, being worked out. Some people refer to it as "The Whoosh": an initial large drop on the scale.

Don't worry about what is water weight, what's fat, etc. Just focus on being consistent and following the trends. You will NOT be losing 9 lbs every 12 days very often if ever again.

lgfrie

If you start a diet and are in a calorie deficit, you will lose fat in accordance with your calorie deficit, and any weight loss beyond that will be water weight.

So, a simple example. You start a diet that has a 1,000 calorie per day deficit, which is 7,000 calories per week or 2 pounds. A week later you are 5 pounds lighter on the scale. Obviously you have lost 2 pounds of fat, and an additional 3 pounds of water.

But let's say that instead of the scale showing 5 pounds, it shows 8 pounds lost. Well, you've still lost the same 2 lbs of fat but now you've lost 6 lbs of water.

Let's say the scale shows zero pounds lost. In this case, you've lost 2 pounds of fat and retained an extra 2 pounds of water.

There is always a possibility (indeed, a likelihood) that your calorie deficit calculation is a little off. So, for instance, you or MFP or other tool of choice may think your maintenance/"TDEE" caloric level is 2400, from which it comes up with 1400 as the target level for losing 2 pounds per week. That number could be off in either direction by a couple/few hundred calories. So it's plausible that instead of losing 2 lbs of fat, you actually lose 1.7 or 2.3. Very possible. It isn't an exact science unless and until you compute your personal TDEE from 6-7 weeks of good data. But it will be in the ballpark.

To be blunt, the notion that the first 14 or 30 days is water loss is complete nonsense, as is the notion that the first 5 % or x% is water. Water is not lost as a percentage of your weight loss. And it doesn't take 14 or 30 days to drain off the excess water. It takes 4-8 days for water to rebalance in accordance with your new caloric, sodium, and carb levels, but most of that will occur in the first 2-3 days.

Based on the #'s you've provided, i.e. losing 12 pounds in 9 days, a good guess is that you've lose 2-3 pounds of fat and the rest is water. It could be 1.8 or 3.5. It isn't an exact thing. But I would put my money on 2-3 lbs of fat lost.

That said, I agree with a comment above that you should just ignore this for now. Get into your diet, eat a consistent calorie deficit and get some exercise, and the results will come. Scales are great for accountability but not so great for telling you how much fat you've lost in the last week or two.