my modified south beach diet

A year and a half ago I easily lost 19 pounds in 3 weeks on a modified version of the south beach diet. The modified diet came from one of my friends who is a phd and a heart researcher. He uses the diet but eats mostly fish instead of red meat while on the diet. Anyhow, I kept the weight off for a year but slowly started to gain it back. Now I've given 15 pounds back and I've decided to go back on phase I of the diet. By way of background, I'm 6 ft tall and my target weight is 185. monday (NYC) - weight 202 - breakfast: Iced coffee with skim milk for breakfast. - Lunch: Salmon teryaki from tokyo lunch, minor vegetables, no rice - Dinner: left over smoked chicken and ribs Tuesday (NYC) - weight 202 - breakfast: Iced coffee with skim milk. - Lunch: halal cart for chicken and lamb, salad, no rice, a little white sauce on the side for dipping - Dinner: left over smoked chicken, carrots, pineapple Wednesday (NYC) - weight 199 - breakfast: Iced coffee with skim milk. - Lunch: Eel don buri from tokyo lunch, vegetables, no rice - Dinner: salad Thursday (Princeton) - weight DK - breakfast: Iced coffee with skim milk. - Lunch: seaweed and octopus salad - Dinner: 9 pieces of sashimi and red snapper teryaki (bleh), no rice Friday(Princeton) - weight (DK) - breakfast: Iced coffee with skim milk. - Lunch: Salad with hard boiled egg and bacon bits - Snack: 15 pistachio nuts - Dinner: 15 nuts and a nectarine - Exercise: 2.5 hours of tennis Saturday (NY) - weight 197 - breakfast: Iced coffee with skim milk. - Lunch: Antipasto salad - Snack: 15 pistachio nuts - Dinner: grilled porterhouse steak, corn and lobster - Exercise: 1.5 hours of tennis, 45 minute brisk bicycle ride Sunday - tbd, interested to see what happened, corn is a no-no, porterhouse is not lean enough and antipasto salad had some high fat cold cuts/cheese.