30-40lbs weight loss

Yeah, set up your Goals to "Lose 1 pound per week."

Log food.

In a month, you'll have enough data to look at your progress and see if you are losing one pound per week. If not, adjust calories.

Here:
https://community.myfitnesspal.com/en/discussion/1080242/a-guide-to-get-you-started-on-your-path-to-sexypants/p1

Calorie intake is everything

If you take more calories

Just burn it by exercise(hiit) burns most calories

I'm nearly the same size/shape as you - I'm 5'3 and about 152 pounds; I also want to lose about 30.
It's hard being short because there isn't much wiggle room in the calories you can eat - I'm trying for 1200/day...that doesn't leave room for a lot of food, and I like to eat!
Track EVERYTHING that you eat, and look at how many calories in each food - try to each A LOT of fruits and veggies (calorie dilute foods). Just realize that it has to be a total lifestyle adjustment - it's a forever way of living, not just a 'diet' for a short time, because you'll just gain back the weight if you go back to the way you were eating before.
I have a sedentary job, not sure about you...but I try to take a walk break every day, and walk the dogs at night or shoot basketball with the kids, or some quick kettlebells in the morning, garden chores, just something physical to keep your strength and activity up.
Good luck! Friend request me if you want, I share my food log, I find that's helpful to see what other people are eating too (or I'm just nosy

sam7778446 wrote: »

Calorie intake is everything

If you take more calories

Just burn it by exercise(hiit) burns most calories

Calories are the key, that's for sure. But exercise selection isn't as simple as "do HIIT", unfortunately - even if weight loss is the only goal.

HIIT burns more calories per minute, but isn't necessarily the way to burn the most total calories. HIIT also tends to be over-hyped in the blogosphere these days.

True HIIT is time-limited: We can't keep up high intensity for very long. Moderate/low intensity exercise can be done for longer time periods - if a person has the time budget for it - and burn more total calories. The EPOC (excess post exercise oxygen consumption, "afterburn") from HIIT is over-rated, as it's a percentage of the base calories burned in the exercise session. Lower intensity exercise also has EPOC, and while the percent is lower, the total caloric value of EPOC can be higher because the number of calories burned in the longer session is higher.

True HIIT also tends to be more fatiguing, and that's particularly a concern for new exercisers whose goal is weight loss. If a person exercises to exhaustion, then drags through the rest of the day (moves less with home chores, non-exercise hobbies, and such; plus rests/sleeps more), that reduced activity reduces the net calorie benefit of the exercise.

On top of that, some current exercise modalities called "HIIT" - such as high-rep low-weight strength circuits - can be more prone to poor form occurring (due to speed and/or fatigue), thus increase injury risk.

High intensity exercise, in the long term, has a role in a well-rounded exercise program. But from a fitness perspective, if elite athletes don't do all high intensity all the time (and they don't), why would us regular duffers? High intensity exercise, from a fitness perspective, is more of a side dish or condiment, not the main meal.

I'd encourage the OP to do some strength exercise (to keep as much current muscle as possible alongside losing fat), and find cardiovascular exercise that they personally find fun and energizing. Fun exercise tends to actually happen, while extreme and unpleasant exercise - however theoretically beneficial - tends to be procrastinated, skipped with the slightest excuse, and eventually may even be given up altogether.

ETA: If this comes across as harsh, I'm sorry. I don't mean it that way. The over-hyping of HIIT in the blogosphere by fitness influencers and marketers is one of my pet peeves, so I'm probably over-reacting. Too many trendy sites are selling it to people pursuing weight loss without a full explanation of the pros and cons, and some even seem to claim that it's the only way. It's not. High intensity work does have some special benefits, but works best in an overall program where someone has developed good base fitness, then adds higher intensity gradually to avoid injury, burnout or excess fatigue.