Look at the title of the article. Nobody here is claiming that 5:2 or any fasting program is magic. That would be ridiculous. So before we even get into the article we can see that it is going to be a straw-man attack.

From the article:
“The JAMA study used alternate-day energy restriction for the fasting group, whose members ate one meal containing 25 percent of their usual daily intake on fasting days and “feasted” on 125 percent of their usual daily intake on the other days, for an average 25 percent calorie reduction. The calorie-restriction group reduced calories by 25 percent each day, spread over three meals. Participants started out sedentary, and researchers asked them not to increase activity.”

NOBODY who promotes intermittent fasting, to my knowledge, advocates increasing usual calorie intake on non-fasting days. That is just ridiculous. So the study is based on a flawed premise from the outset.

Yes, daily calorie restriction is effective. But most of us have tried that and struggled with maintaining it and fitting it in with our busy lifestyles. The convenience of 5:2 is what is, so far, making it a breeze for me. I only need to plan special food on a couple of days per week, not every day as I would if I were eating a calorie-restricted everyday diet. And that “special food” is as simple as boiling a couple of eggs in the morning and tossing them in a lunchbox with a bunch of lettuce (or steamed green vegetables) and a tomato or two. Done, and I can eat normally every other day.

I get that some people find intermittent fasting difficult to follow. They should probably find a different weight loss method.

I know one of the authors of that article. Using the word discredited in your title post may be a little strong. They were comparing CER vs IER and the results were very similar, both lost weight. The study only looked at weight loss out to 6 months. There is no magic involved with 5:2. You see posts here all the time from people expecting magic to occur and when it doesn’t they feel like they’ve been duped. People that continue to make poor food choices and expect to see results are living in fantasy land. They tend to last here for a short period of time, argue that they have been conned and move onto the next magical cure.

Here is an important quote from the paper “In the interventions lasting 48 months (a mean of 3 to 6 kg (3% to 6%) weight loss was maintained with no groups experiencing weight regain back to baseline levels.” If you treat 5:2 as a continual eating pattern rather than a diet then it will work. It works even better if you couple 5:2 with good food intake rather than poor choices.
I often use the example that eating 2000 cal of sugar per day will produce a very different result to eating 2000 cal of broccoli per day.

Go to the maintenance section and ask successful weight losers and maintainers how they did it. There is a common theme to their responses. Eat healthy foods, eat foods that satiate you, eat foods with lots of fibre, avoid processed foods. If your great grandmother wouldn’t recognise it as food, don’t eat it. If you purchase the majority of your food from the central isles of a supermarket your asking for trouble. Eat whole foods.