Special Diets/why people gain weight
Are carbs or calories the reason why people gain weight or what can it be?
Thank you for your question.
While it would be great to have a simple answer to this question, there isn't one. People gain weight for a variety of reasons: genetics, lack of exercise or adequate exercise, diet, hormones, disease, age, and so on. That's why there is always a notice to see a doctor before starting any kind of diet or exercise routine.
Here's a good example. I have a colleague who has a thyroid disease. When her thyroid is out of balance, she tends to gain weight (or not lose it easily at all) and her skin gets very dry. She has a good diet -- a balance of proteins, complex carbohydrates, and good fats -- all in moderation, but struggles when her thyroid is out of balance. Which is not to say it is out of balance all the time, because it is not. She takes a daily medication and sees an endocrinologist to address the issue. All that to say that there are numerous reasons why someone would gain weight.
When I gain weight, it's because something is out of balance. I need to exercise strenuously at least 45 minutes a day, at least 6 days a week to maintain general health. Because I eat nutrient-dense foods that also tend to be high in fiber, the calorie count tends to be lower (even if there are plenty of complex carbohydrates) and I stay full for longer lengths of time. But, if I don't eat those kinds of foods and don't exercise regularly, I will gain weight.
I wish I could give a sweeping answer to this question, but I can't. However, I'd bet that if people exercised or even walked regularly every day, limited their portion sizes, and ate more whole foods (colorful fresh fruits and vegetables, brown rice, quinoa, oats, etc.), they would likely keep their weight lower than if they didn't exercise and ate processed foods high in salt and sugar.
I hope this helps.