Any advice to lose weight?

Good advice from Sollyn above.

I'd add this: If you're using a heart rate monitor or fitness tracker to estimate calories burned from doing hot yoga, and eating all those calories back, there's at least a fair chance those calories could be overestimated. (This could be true whether you're adding the exercise sessions to MFP manually, or syncing a tracker/heart rate monitor.)

Why do I say that? Devices are often using heart rate to estimate calorie burn. But heart rate goes up for some reasons that correlate with calorie burn (such as oxygen consumption during aerobic exercise) yet can go up for other reasons that don't correlate with calorie burn (such as high emotion/stress, strain, and a hot environment, among others).

Depending on the specific device's algorithms (about which the companies typically aren't very open), the implication is that calories may be over-estimated for exercise in hot conditions. I know for a fact that my device - a good brand/model generally - will tend to give me a somewhat higher calorie estimate for the same duration/objective-intensity exercise on a very hot day compared to a cool day.

Another possibility, though maybe less likely in your case, is if the hour of hot yoga is more fatiguing than the exercise you've done previously. It's possible for over-exercise to trigger fatigue that reduces our calorie burn from doing daily life stuff, because we may drag through the day, rest more, maybe sleep more. It's not super common to have such a big effect from that that exercise calories are totally wiped out, but a person can net fewer calories than expected that way in some cases.

Also, if the exercise change is relatively new, say less than a month, you could still be experiencing some water retention effects that could temporarily mask fat loss on the scale. There's more to it than that, but if it's a shorter time, and you're not seeing obvious gain, I'd suggest hanging in there a bit longer - 4-6 weeks, or a whole menstrual cycle if you have those - to see. I can be sub-ideal to keep cutting and cutting calorie intake based on shorter-term weight changes, but in most cases the 4-6 weeks/whole cycle thing will be a pretty good indicator.

An exception might be if you're going for a very slow loss rate, like half a pound or a quarter kilo per week or less. That gradual fat loss can take even a bit longer to show up clearly amongst normal day-to-day water/waste fluctuations, as I've seen in personal experience.

Best wishes!

Yeah, your more than likely eating more than you think, most do, and walking for a hour by a lake compared to yoga is probably not the same as far as calories burned. It's all a guessing game at best anyway and if the expected outcome is some exact number based on math, well then most will be disappointed. Give the numbers game another go, it's pretty much your only option.

One day at a time! I weigh myself everyday- it keeps me on track. Even small increments add up as long as it’s moving in the right direction. Another strategy I use to keep me focused is to go to a department store just to try on clothes. I get so frustrated, but then power trip myself by asking, “what am I going to do about it?” The reality is I’m overweight but when I discipline myself to take control of what I’m eating, how much of it and moving my body, I’m empowered to reach my goals. You can do it and so can I!!! 😃