Hi Stephanus and welcome:

I think you are making it much too complicated. If you eat more calories than your body needs, whether each day or each week, it will store the excess calories for later use. If you eat less calories than the body needs, it will use previously stored calories to make up the difference.

It makes no difference when you eat the calories for that equation to operate. So eating once a day or six times a day, it all comes out the same.

Here are some 5:2 tips: https://thefastdiet.co.uk/forums/topic/the-basics-for-newbies-your-questions-answered/

Good Luck!

There are actually many factors involved, it isn’t just calories. However over-eating will likely lead to gaining fat, even if it is just over-eating for a short period of time.

For many people, there is a lower insulin response to sugars early in their day as compared to later in the day. However it can often take a long time for insulin to return to fasting levels. Even spreading meals apart by 8 hours may not be completely enough. The main problem is that we don’t have an easy way to measure blood insulin and it is possible there are wide variations between people. It is easy to measure blood glucose and it likely follows that the higher the blood sugar the higher the insulin. This isn’t always true though as shown by type I diabetes.

When it comes to blood glucose I know that mind drops quite a bit after about 20 hours of fasting. After about 90 minutes or so it climbs back up to more normal levels. When I fast for multiple days the blood glucose will even go a little lower but generally I don’t notice it like the drop around 20 hours. The point is these timeframes don’t really fit into a eating two widely spaced meals in a day.

While I strongly discount the overly simplified calorie math, I have to agree with simcoeluv that overeating in two meals instead three won’t buy you much.

Fasting does buy a lot though. When I was using calorie restriction, I was trying to eat less than 14000 calories a week. With 5:2 I’m actually eating around 15000 calories a week, but I weight a lot less and I have a lot less body fat. When I reduce the food consumption it has more impact than just a continuous diet. I’m also trying to build muscle so I have more of a difficult balance. If you cut calories too much it is possible to lose lean body mass.

If you really don’t want to fast, then probably the best thing to do is to cut as much refined sugar from your diet as possible. That can have a great impact. A second thing to do is reduce the amount of simple carbohydrates consumed.