Muscle weight?

A month ago: water retention and a bit of muscle could be the culprit.

As for eating back (too many) exercise calories, I like this calculator to judge how realistic my fitness tracker's estimates are: https://exrx.net/Calculators/WalkRunMETs
Set the calculator to 'net' instead of 'gross' if you're comparing to the adjustment you get in MFP.

It's very, very unlikely that muscle mass gain will happen fast enough to mask a meaningful rate of fat loss on the bodyweight scale.

A really good rate of muscle mass gain for a woman, under ideal conditions, would be about a pound a month. Ideal conditions include a good, challenging progressive strength training program faithfully performed, very good overall nutrition (especially but not exclusively adequate protein), relative youth, favorable genetics, a calorie surplus (i.e., weight gain), and probably some other things I'm forgetting. (For a man, maybe 2 pounds a month.)

It's not that you can't gain muscle from running or in a calorie deficit, necessarily, but it would likely happen even slower than that pound a month.

On the flip side, a pound a month of fat loss is about the slowest observable fat loss rate, and that can even play peek-a-boo for many weeks with water/waste fluctuations on the body weight scale.

It's likely that if running is new to you, you'd add some water weight. Also, Lietchi's right about the issue of net vs. gross calories, and potential over-estimates of exercise calories. Retro has a point about dramatically increased exercise possibly bleeding calorie burn out of daily life (resting more, maybe sleeping more, less spontaneous movement like fidget-y stuff and more, etc.).

Yes, cardio burns calories . . . but beyond that, it doesn't all by itself "make you lose weight". (I did meaningfully large amounts of cardio for around a dozen years, and stayed class 1 obese, because the calories are pretty easy to eat back when not calorie counting. If you're counting, accuracy is still important.) And yes, cardio is good for a body health-wise - worth doing. But the water weight issues and the calorie estimation issues (NEAT and exercise) do matter.

You've lost a lot of weight, you look great . . . you're probably at a point where it's realistic to expect weight loss to slow down - or to slow it down intentionally. If you're calorie counting, I don't know what loss rate you're shooting for, and you don't say how fast you lost in (say) the month before you starting the 3 miles per day. Knowing that would help us give you more nuanced answers.

Right now, my bet would be on water weight weirdness from the new exercise, and the likelihood that you'll see a scale drop sometime in the next month, assuming you're not both overestimating and eating back those exercise calories.

Hang in there, you're doing great, the running is worthwhile health-wise, and the weight question will sort itself out fairly soom.

Best wishes!

PrincezzPri wrote: »

Cardio make you lose calories, not weight.

That makes no sense at all. Sorry. A calorie is a unit of measurement, such as grams, watts, feet, degrees celsius... You also don't say that switching on the light makes you lose watts. Every movement uses energy as source, and just existing does as well. And this energy is commonly expressed in calories. Or kilojules in some parts of the world.

If you’re running regularly, grab a polar chest strap to measure calorie burn (etc).

For example: I do a 1hr hike 1-3 times a week. My wrist-worn Fitbit estimated 630 cals burned while my chest-worn polar estimated 320.

OP you have had an especially aggressive rate of weight loss.

Based on information provided in a previous post you have lost 2 more pounds in less than a month.
It’s not the 3 or more pounds you lost earlier in your process. And that is to be expected.

I’m sorry it’s not faster. But you really don’t need to worry about your rate of weight loss.

You've probably upped your calories to overshadow any weight loss that the running would produce.

DrBenja wrote: »

Jogging can build muscle, especially in your legs, which may offset fat loss on the scale. Muscle is denser than fat, so it's possible you're still losing fat but gaining muscle.

TO is not building muscle in such quantities that it shows on the scale. That requires a bit more than jogging a short distance a few times per week, especially for a woman.