I’ve been following a low glycemic diet for decades, but Taubes explains technically why it minimizes fat deposition.
If I start eating snacks like candy or corn chips, the weight gain is immediate and obvious. Not all calories are the same - some foods just “go to your hips”.
But if I continue to eat high carb, there is a weight gain that is much harder to shed.
Read Taubes for references to the scientific literature.
This does not happen with protein and fat consumption. If you force yourself to overeat those foods in the absence of carbs, which is not easy, they will be simply eliminated.
What you're referring to (excess carbohydrates converted to fat) is denovo lipogenesis which is exceedingly inefficient and rare in humans.
You can't get fat on a diet that is strongly deficient in carbs, while it's easy to get fat on a diet containing high proportions of fat and carbs.
The Eskimo subsist on meat and blubber alone. Roald Amundsen ran the experiment on himself and confirmed it.
The ethiopians have a diet of mostly carbohydrates (>70%), and are extremely lean.
Taubes is a bullshit artist who cherry picks data to sell books.
Ethiopians are hungry.
We humans in rich countries eat ad libitum. Any dietary intervention that helps us feel less hungry will lead to a reduction in the calories we consume.
Second, what elite athletes do often does not translate to what laypeople can and should do. Most elite athletes have a tremendous gene advantage over other people, not to mention the time, energy, diet, coaches, etc., that allows them to push beyond what the average person can tolerate. It's almost ridiculous to say, "Micheal Phelps does xyz in the pool and you should too if you want to improve your health in the most efficient way possible."
See https://bodyrecomposition.com/training/endurance-training-me... for an example. The German track cycling team does 90+% of their training at low intensities. For an event lasting 4 minutes. The simple fact is that at the highest level, all pure endurance athletes do mostly aerobic work.
The reason I separate elite athletes from others is that they are genetically different than the average person. To be an elite athlete in a super competitive sport, you are not representative of the normal population. You can likely train harder and longer and most likely have some type of other genetic advantage. It's far better to focus on studies that look at normal people rather than elite athletes.
Anyway, to go back to your original question, asking how HIIT is more effective, you are right that it is not necessarily effective at every endeavor. But literature shows that for the average person, doing 10 minutes of HIIT can be as effective in losing weight, gaining muscle, cardiovascular fitness, etc. as doing something like 30 minutes of low-intensity exercise.