Chocolate consumption per week

I have 20g of Lindt 70% dark every single night. It's my little treat with a cup of tea, and it makes me happy.

So long as it fits your calories, and isn't edging out more nutritious foods, have at it!

You can have all you want provided it fits in your overall calorie target.

If your only goal is to lose weight, the answer is "as much chocolate as your calorie budget will allow".

If you also value your health, the answer would be more like "as much chocolate as you can fit in your calorie budget while also getting adequate protein, fats, veggies/fruits (the latter for micronutrients and fiber).

Yes, getting too many calories from added sugar is undesirable, but (according to WHO) mostly because when we get too much sugar we're usually going to either (1) exceed reasonable calories while getting adequate nutrition, or (2) not get adequate nutrition within a sensible number of calories, plus sugar can contribute to dental problems.

There can be a couple of personal problems with too much chocolate or too much sugar. First, sugar intake may spike blood sugar, and the subsequent crash can trigger cravings. Second, chocolate (or other sugar-y things) tend not to be very filling, which can cause appetite problems.

If you crave that chocolate treat, I agree that portion-controlling it (and choosing really good chocolate!) can be a good way to go.

There are also some slightly more nutrient-dense things with some nice chocolate flavor that may scratch the itch. Chocolate peanut butter powder can be added to various foods (yogurt, fruit, etc.). Cacao nibs can have a nice flavor, and add some crunch on top of various foods. (IME, different brands of nibs are more flavorful than others. Some don't have much taste, others are super good.)

Plain cacao or cocoa powder (no sugar added) can give a rich chocolate flavor to things, including some savory foods. (I put some in things like chili or black bean soup. Think about mole sauces, though the chocolate flavor there is more a note than a main feature.) There are different versions of cocoa powder that work better in certain cases, but I'll leave that for those interested to research. Cocoa/cacao powder is not necessarily extremely high calorie, though raw cacao can have more fat in it. (The brand of cacao powder I use has 60 calories per 2.5 tablespoons/15 grams. One tablespoon per serving adds some nice flavor - and antioxidants - for 24 calories.)

It's the fats/sugar in chocolate that primarily increase the calorie count. We need some fats, and very low-fat chocolate (candy) is not IMO very nice. Sugar can be more flexible. Read labels.