re: Biology, Chemist and Biochemist OTers: Help me understand weight loss.

I'm none of those in the title, but my company just did a 17 person fat loss diet challenge. We had 8 people who did very well. We all were calipered by the same person beginning and end. Went for two months.
There was a few interesting things.
The top performers all lost roughly the same amount of body fat but different amounts of weight. We all lost between 1# and 1.5# of fat per week.
The two winners did not starve themselves. They both were the only ones to plan and measure their food out. The person who lost the most weight was visibly thinner, but lost less fat.
Many did different diets and had similar success. Do not drop your calories too low. Eat and exercise. Cut sugar and try to loose 1.5 pounds a week after week one. Week one would be a little more.
The winners both lost 12# compared to the top loss at 28# over two months. Winners were able to lift weights, do some cardio, and they timed their meals.