You’re right. The consensus on the dangers of sugar is widely accepted in endocrinology and biochemistry. But a lot of nutritionists argue that a calorie is a calorie regardless of the source – they seem to be startlingly/conveniently naive.
Calorie == calorie is more like a loose correlation. I have successfully used purely calorie reduction strategies to lose weight and modify eating habits with some success. However there are two caveats: perhaps I would lose similar amounts of weight if calories came mostly from carbs & protein vs. protein & fat, but health impacts beyond weight will surely be impacted, e.g., cholesterol and the "skinny fat" scenario.
Annecdotally I also find that complex carbs like oats may be modestly better for weight than equivalent processed carbs but more importantly they control hunger more. A bit of shopping around will also find specialty pasta that uses a roughly calorie neutral fiber mixed in with flour for pasta that is high in fiber and has half the calories. This too appears to have a significantly different impact on appetite. (Fibre Gourmet is one such brand, texture of cooked pasta is slightly different)
So calories ~ calories for raw body needs of energy, with correlation varying on particular source pairs, but secondary effects are significantly different. Also general human metabolism is still not fully understood, with significant gaps, and anyone claiming to have "the answer" or a perfect diet are at best incorrect.
As a side note, it is difficult to manage hunger at a reduced calorie diet with only calorie-dense food, which makes adherence to a low calorie diet much harder. On average I have found that less calories dense foods tend to be healthier at the same time that I may eat larger volumes of them and feel more satisfied.
Source: Me, a non expert with annecdotal experience and a reasonable amount of non-expert research for balancing my own nutrition & health.
> The American Heart Association suggests a stricter limit for added sugars — no more than 100 calories from added sugar a day for most women and no more than 150 calories from added sugar a day for most men. That's about 6 teaspoons (24 grams) of sugar for women and 9 teaspoons (36 grams) of sugar for men.
I think I just used 1/3 of my recommended limit in my tea.
While sugar when added to food, and especially when added to beverages, is bad, the conclusions of the study seem consistent with sweeteners being as bad as sugar.
According to this meta study, the sweeteners do not cause any cancer risk, but in the long term they significantly increase the risk of diabetes and of various cardio-vascular problems, without providing any reduction in obesity.
So they appear to be no better than sugar.
It seems that the best strategy is to satisfy one's craving for sweet things only with naturally sweet fruits and vegetables, raw or cooked, and without making juices out of them.
I have actually given up on using sugar some time ago, because both my grandfather and my father had diabetes at old age, so I do not want to repeat their fate.
Now, after becoming dis-habituated with sugar, all the fruits and also many vegetables like red bell-peppers, carrots or even red onion, feel extremely sweet, unlike during the time when I was frequently eating food with added sugar.
So I no longer crave for sweets, even if I had not expected that this is possible.
>there is no clear consensus on whether non-sugar sweeteners are effective for long-term weight loss or maintenance
If you consider the introduction of non-sugar sweeteners as the beginning of an experiment, you would have to conclude that if there was a major benefit regarding weight loss, it would very clear by now if the experiment was a success.
The right thing to do is simply not crave sweets.
It's just one of many chemicals which is not nearly as risky when not in its chemically pure form.
Modern medical consensus is that added sugar should be avoided as much as possible.