There is more to trying than being told. Also the level of effort/sacrifice to have the same impact with vary by age and individual.
Trust me, I'm the most OCD guy ever. I literally just ate the same meal every day for 5 months. I've tried the craziest diets. Compliance is not the problem in people like me. It's something metabolic.
I think it is, if it is being recommended to the person to lose weight.
I tried and failed to eat less food for decades. Ultimately it was total abstinence for many hours at a time that proved to be sustainable and actually easy after 3 months.