Drop the Diet Pepsi. Your body treats fake sugars and sugar substitutes in a very similar way that it treats regular soda, in terms of your insulin production.
Put less emphasis on day to day scale results. If you are doing OMAD and tracking calories, I would suggest weighing once a week, or keeping track of a weight moving average for the week.
Here is the deal on the exercise. At your age and weight, you BMR is likely around 2300-2500 if you are in weight loss mode. So if you are eating 1800 a day, your deficit is probably around 500-700 a day. Not enough for 10 pounds a month. So you have two options, you can cut your calories down to closer to 1300-1500 a day, or you can get active. When you are at your heaviest is when you get the most caloric burn from things like walking, yoga, gentle cardio etc. For me personally, I choose to eat a bit more, and exercise a lot. That’s created a calorie deficit per day of 1500+. If you are looking for 10 pounds a month, you need to get your daily calorie deficit to around 1200.
57M, 6’1, SW 270, CW 210, GW 210. Lost 60lb in 4mo, Apr-Aug. Did it with 2MAD, 16:8, and one 88hr fast every other week. That along with exercise; lifting 90min 3x/week and cardio 30min 5x/week. For maintaining wt I stopped the extended fasts, kept everything else, wt has held steady for 4wks so far. The longer fasts reallly drove the wt loss, I lost 9-12 consistently each time. Makes sense, you have to lose wt not eating anything for nearly 4 days. Would gain back 3lb within a few days of breaking fast, still a net 6-9 lbs per 2 week. Not saying this is the perfect plan for everyone but it worked beautifully for me.
Pretty much everything I suggest will be controversial and down voted, iirc – it’s been a minute since I’ve posted here.
The more meat you eat, the healthier you will be, in every aspect of your life - mental, physical, inside, outside, head to toe.
The fewer grains and fiber you eat, the healthier you will be. You will either completely correct or at least massively improve on your gi and bowel issues (gas, bloating, indigestion, heartburn, constipation, hiccups, etc) if you eliminate them from your diet completely.