I found myself asking the same question about Robert Costa. There's a lot of speculation and it gets tough to figure out what will work best for each person individually.
I believe that there is some truth to the mindset behind weight loss that Priyanka talks on in the article about Robert Costa Weight Loss but that's most likely backed up with some decent lifestyle changes.
A great way to begin losing weight is to work towards intermittent fasting. I stop eating after dinner at about 8pm or 9pm (depending on how busy my day has been). The next meal is normally at noon the following day. I do this to allow my body to finish flushing out the junk from processing what I have eaten.
Typically I'll drink about 2 litres of water through the morning after I wake up. I'll also drink lemon and ginger tea for the alkaline benefits that brings, but I'm really trying to allow my body to finish detoxifying before I break the fast and eat.
I don't feel hungry, and previously I would have oats for breakfast with dates and a litte honey. Over a few weeks I pushed the time I had this out later and later.
What I've found is that if I eat in the morning I feel hunger thorough the day a lot more. Lunch is a mix of fruit, and dinner is normally vegetables and sometimes a small amount of meat. Im working on cutting back more on the meat, as much as I currently love it, as I find that I'm feeling heavier and more sluggish eating it.
I'm planning on putting some info together on the steps I'm taking and the results I'm seeing do others can find out about intermittent fasting.