Answer:
Hi, you haven't provided the options to the question so I will just give the answer in my own words and you can check with the options.
Answer is: HE LOWERED HIS METABOLISM BY TRIGGERED MECHANISMS DESIGNED TO PREVENT STARVATION.
Explanation:
When a lot of weight is lost, the body starts trying to conserve energy by reducing the number of calories it burns, which causes hunger, tiredness and increases food cravings.
These effects can put a stop to weight loss and make one feel miserable such that one abandons the weight loss efforts and regains the weight.
This phenomenon is the body's natural mechanism to prevent starvation and is often called starvation mode.
Component of cabbage soup and salad causes weight loss because it drastically limits calories.
In Elroy's case, he decides to do a crash diet which starts with cabbage soup and salad and loses the weight at first but he regains the weight back quickly because he didn't only lose fat weight, he also lost water weight and may even include muscle.
Muscle loss causes the metabolic rate (the rate at which the body burns calories) to reduce which result in burning of fewer calories and also weight regain.
Therefore, the likely reason why Elroy quickly puts the lost weight back on is because HE LOWERED HIS METABOLISM BY TRIGGERED MECHANISMS DESIGNED TO PREVENT STARVATION.