I have trouble imagining that it would be better. Look at people who come into access with large sums of money for reasons outside primarily mental achievement - athletes after leaving pro sports, musicians after they stop performing, actors after they stop acting, lottery winners, and so on. Some quick searching turned up articles like this [1]:
"The researchers found that the athletes' weight held steady for over 100 years, with the majority of them weighing in at what is considered "normal," -- i.e., with a body mass index (BMI) between 18.5 and 24.9. However, around 1991 the average player's BMI began to rise, and over the last 25 years nearly 80 percent of players fall into the overweight or obese category with a BMI above 25. "
There's a strong correlation between socioeconomic status and obesity, but that doesn't mean it's causal. Obesity is primarily driven by a lack of impulse control. If you force yourself not to over-eat, you could live off of even McDonalds without becoming obese.
[1] - https://www.sciencedaily.com/releases/2016/09/160930085937.h...