Could someone please explain this to me

Muscle doesn't weigh more than fat, but it's thinner, so more muscle fits in the same place as a pound of fat...If you are building muscle, your weight could go up while you are looking thinner because the muscle is replacing the fat. I believe the increase will be temporary (once your muscles start working better you should start losing again).

I only weigh myself once a week, because my weight can vary up to 5 pounds day to day. If you get on the scale every day or every few days, you start to get discouraged.

It's definitely not muscle. The average woman will put on no more than 5 lbs. of muscle with serious weight training over the course of her entire adulthood.

But you don't give us much to go on here.

Are you sticking to your calorie goal? Do you eat your exercise calories back? Do you zig-zag? Do you weigh your food on a kitchen scale? When you weigh yourself, is it on a reliable scale? Is it always the same scale? What do YOU think could be causing it? Etc...

The reason muscle weighs more is that it is denser then fat. This is one of the reasons a lot of us try to focus on nsv (non scalevictory) more then the number. It sounds like you are doing great.

I sooo know all about that! I had to start weighing myself once a week. Every Monday morning. Great Advice!

I agree that you're probably building muscle and losing fat. And as someone else said, muscle takes up less space than fat, so you're looking thinner while you're not losing weight.

The scale is not the best measure of fitness and health. Try taking your measurements regularly, instead of weighing in regularly. Notice how your clothes fit. Notice how your body feels, how strong you are becoming, how much more energy you have. Those are better measures of your health/weight loss journey than the scale can ever be.

You are right. Muscle doesn't weigh more than fat-- but it takes less room to occupy space as someone has posted. What's happening to you could be what's known as "converting". Converting fat tissues to muscle tissues-- which is going to cause you to "shrink" but no necessarily loose any pounds on the scale. Since we have more estrogen than our male buddies, it takes us longer to "lean out" if you will. If you are lifting, you'll convert as your metabolism demands change, and boday fat percentages will begin declining-- this takes time and its glacially slow, but it happens.
Pay attention to what you are eating-- log every calorie consumed, print out the reports and see if modifications are needed (Do this weekly at least). Fat burns 4 calories an hour (on the average), muscle burns 9 calories and hour (on the average). Make sure that you are consuming enough appropriate calories for your activities and level of activities.
And hang in there. I've been at this stage longer than I care to admit. If you are within the last 10-15 pounds of your goal weight, eat as "clean" as you can, watch for "hidden" things, especially sugars and salt.
If folks are seeing "less" of you, you are ultimately doing the right things-- have patience and don't give up...

As stated before, 1lb of fat = 1lb of muscle. Don't be frustrated that you're not losing weight every day. If you want to know what's really wrong, weigh your food, eat your workout calories, and bust your *kitten* every day in the gym! The more effort you put in to your diet, the easier it will be to diagnose plateaus whether your goal is strength training or fat loss.

Don't been disheartened - if that is a recent photo of you on your profile you are looking great!

If your clothes are feeling better and you are looking slimmer then you are!!!

The problem is there are so many things that can affect the scales! E.G If you move them around the room sometimes you can get a fluctuation of 1/2 pound or more! Also if you don't weigh yourself the sametime every week then that can show a difference. My Hubby does this weighs in the morning and then weighs in the evening and can't understand why his weight has gone up by as much as 6 pounds!!!

Things that impact my weight are!

Eating rice the night before a weigh in! (Around 2 pound impact)
Doing a intense strength workout (don't know why but for two days after I always weigh heavier?! Can be as much as 4 pounds!)
TOM (easily 7 pounds for the first couple of days )
Flying - takes me 3 days to overcome puffiness 7 pounds impact aftet the last flight
Eating MSG - I have an awful reaction to MSG in foods, it takes me about a week to get out of my system.

All of this is not scientifically proven or typical of everyone - but its what happens to me! (I weigh everything, Log weight loss once a week, and log my food & Exercise 90% of the time) So the data is quite good!!!

Anyway hope that helps. Sometimes we just don't know why our weight fluctuates but I would go with how you feel as much as anything.

Charlie x

Doing a intense strength workout (don't know why but for two days after I always weigh heavier?! Can be as much as 4 pounds!)
TOM (easily 7 pounds for the first couple of days )

Regarding the strength training thing, I've been told that after a long run (I am currently training for a half-marathon but did a marathon last fall) I may weigh more because your muscles retain fluid or are swollen while trying to repair/recover from a tough workout. Don't quote me on this because I may have the details slightly wrong, but I do think this is common after a tough workout.

Hi, the body's metabolism is a wonderful thing lol - are you weighing yourself at the same time every week? I only ask because 146 to 151 is only 5lbs and I can weigh sometimes up to 3-4lbs more in the evening than the morning so always weigh myself at the same time in the morning on weigh day. Loads of other factors can come into play with water retention, if you've just eaten a big meal, not getting enough sleep etc and you'll see on the forums lots of peeps will be on a plateau for weeks or months doing the same exercise + cals the whole time and will suddenly drop lbs inexplicably in a week when they've done nothing differently! Good luck, try not to be disheartened with the fluctuations and keep doing what your doing

I totaly agree, some times as salt in take can change your wieght by making your body hold on to more water.