High intensity swimming HELP

Hello, I am a 51year old male who is 5'8" and 225 lbs. I started swimming in Feb 2016. I on average swam 3 days a week and lost about 15-18 lbs and got stronger. I worked my way up to a mile in 45 minutes and then up to 2 miles in 90 minutes. I could not swim this long especially during the week. I would swim the longer swims on Sat and Sun. I am very healthy with no medical issues at all. I started slacking off due to work time constraints getting to the pool early or at the end of the day, fell off my lower carb lifestyle and put back on 8-10 lbs. I read a little on high intensity swimming and I just wanted to see how my proposed program looks to you guys i swim in a 25 meter pool and I call 1 lap as down and back or 50 meters. A mile is (36) 50 meter laps. 3 days a week M,W,F 75 meters at full speed 125 meters at medium speed 75 full 125 medium 75 full 125 medium 75 full 125 medium 75 full 125 medium 75 full 125 medium. total 24 laps 50 meters * 24= 1200 yards. .68 mile. My heart rate definitely elevated the entire time. Total elapsed time is 30 minutes 2 days a week Sat & Sun the same 24 laps as above plus 12 additional laps (50) meters total 600 years for an overall 1800 yards. By the end of this 600 I am cooled down and feeling great. Total elapsed time is 45-55 minutes. I am Hoping by going more days with shorter time, I will not miss days due to less time. Do do you think this is intense enough to shed weight and tone up? I would like to get down to 195 lbs. I will also get back on my lower carb lifestyle to lose weight. Remember I breathe hard on the 24 laps and it feels great. Any help will be appreciated, I am new to this buy want to make my next 50 years healthier and stronger than the first.