Are you talking about Obesity Code? I find it to be quite convincing, he uses many studies to debunk the calories in calories out paradigm and provides ample evidence that obesity is a hormonal problem.
Lost over 100 pounds in 1.5 years after a lifetime of obesity by simply eating less and skipping meals. I've read the literature on both the medical and bro-science side. I know plenty.
Fung's theory prescribes exactly what you did. Eat unprocessed foods, don't eat too much, don't snack all the time, skip breakfast, fast 24-36 hours every now and then. Whether or not you get fat is largely determined by insulin levels and homeostasis. Insulin level is elevated in obese people due to insulin resistance. Fasting and not snacking (and skipping breakfast) help reset insulin "thermostat" to within normal range and maintain it through relatively minor lifestyle adjustments.
Yes, eating too much food can cause weight gain. That is also the simplest and least helpful view that exists. It certainly does not explain how some people can gain weight with a calorie deficit and some people can loose weight on a calorie surplus.
By the way "skipping meals" (aka fasting) is exactly what Dr. Fung recommends to lose weight. Fasting drops your insulin levels and gives your body a chance to burn its stored fats.
This is something I don't quite get about Jason Fung. He is critical of calorie restriction being less effective (he says you will feel more tired). But I'd like to see strong arguments and evidence for that.
He sites several studies including the Minnesota Starvation Experiment[0]. It's pretty simple, if the body gets some calories but not enough, your metabolism is lowered and you have less energy along with a host of other symptoms. This also explains why this is a terrible dieting strategy, once your metabolism is lowered you regain the weight quite fast once you start eating more.
Oh I don't deny I felt like shit and every moment of it sucked. But like most things worth achieving you need to put something resembling effort into it. The results were definitely worth it.