After getting cast in a community theater musical role that required me to wear some slinky dresses in front of hundreds of people, I (a 48-year-old woman with PCOS and an underactive thyroid) lost 30 pounds in 10 weeks last summer, going from 180 pounds to 150, which on my huge-boned and muscular frame, looks positively skinny.
I was already exercising daily (30-60 minutes of brisk hiking or elliptical training every day). What I changed was my diet -- how much I ate, what I ate, and when I ate. I used the Samsung Health app on my phone to start counting calories, which based on my past experience (I gain if I eat more than 1500 calories, hold steady at 1500, and lose only if I'm consistently eating well below 1500) I limited to 1250 per day. I also practiced intermittent fasting by limiting my meals to between 6am and 4pm. Then I rearranged what I was eating to focus on nutrient-rich meals, with adequate protein, vitamins, and minerals, and a minimum of processed foods.
Breakfast around 6am was oatmeal with fresh fruit, or a 1-egg spinach and mushroom omelet with a slice of whole grain toast, or Greek yogurt. Lunch around 11am and dinner around 4pm were things like a tossed salad with light balsamic dressing and some chicken or turkey breast, zucchini "pizza boats," roasted chickpeas with quinoa and cucumber salad, cabbage steaks with a drizzle of olive oil and parmesan, or a quesadilla made with Carb Balance tortillas. I specifically chose foods I already liked, and knew I wouldn't get tired of eating, which helped me stay motivated and not feel deprived. If there were calories left for snacks, I stuck with fresh fruit or veggies or a handful of nuts -- nothing too processed, nothing fried. I also abstained from alcohol. My one big "cheat" was that I still allowed myself a splash of my favorite flavored creamer (pure sugar and chemicals!) in my coffee every morning.
Honestly, after the first couple of weeks, I didn't feel hungry between meals or in the evening, and I was already feeling more energetic. While I've "slipped" a little in the 9 months since (regaining about 10 of the 30 pounds I lost), that's mostly due to difficulties getting out to exercise in the colder months. I expect to lose those pounds again now that the weather is suitable for me to hit the trails -- and now that I have the looming motivation of a couple of summer vacation trips.
I wish you luck!