Before I attempt to answer this, I'd probably want to ask you what you understand by the term clean eating.
Some people would say it's eating 'healthy' but what do they consider to be healthy? No sugar, no butter, no pizza? Some may say being fat free or carb free. Or perhaps it means not eating processed foods but then you see them taking protein powder...
To be honest, there is no real definition to eating clean, just opinions. The best thing to do is not label food as clean/dirty or good/bad. Instead, focus on the 80/20 rule.
The 80/20 rule means keeping 80% of your food consumption to foods that have not been removed from their original state. This would include foods like fruit/veg and minimally refined or whole carb sources like oats, potatoes and brown rice. It means getting your fats from foods such as avocados, olives and nuts rather than foods which have added fats.
So the 20%? This is where you get to eat the crap! A chocolate bar, a few slices of pizza, a doughnut, refined/processed foods, whatever you can fit in to your calories/macros if you're counting. If you're not counting, it's a fifth of your daily consumption.
This works because it's non restrictive. I mean honestly, unless you're an athlete, how long can you really keep up any sort of strict diet that only allows certain foods. Ever had the experience of wanting what you could not have? Well that's exactly how restrictive eating makes you feel. When you do stop being so strict, the weight could come back on quite quickly.
So the answer to the question is no, you do not need to eat 'clean' to lose weight but for the purpose of your health and function you do need that 80% of nutritious foods.
To learn more on nutrient dense sources and how to make the best choices when it comes down to weight loss, plus lots more free help on losing weight and working out your calories/macros join our closed Facebook group www.facebook.com/groups/lift365