We set these random targets that seem to often have been plucked out of thin air. "Oh I think id like to lose 20 kilos. Where on earth did this number come from and what is it based on? I have seen people lose huge amounts of weight. They have gained muscle, strength, stabilized blood sugars, started to have more energy and yet still feel like they have failed because they didn't reach their said goal of whatever ever number they decided they should have lost. Take for example someone who has decided that their ideal weight is 65 kilos. They may be 67 kilos. They may have already lost quite a bit of weight over time, their health is improving but they feel like they will not be happy till they reach their said goal of 65 kilos. It is possible their body is at its optimum weight at 67 kilos. Lets throw in genetics, height etc and work with the idea that this is a good weight for them. Assuming they are fit and eat well. Their body may resist any more weight loss. It is happy at this set point and any more weight loss will be quite difficult for this person. Cue another blow to self-esteem. The internal dialogue starts to step up a notch. "I am hopeless, its only 2 kilos, why cant I do it." The voice rarely says "Hey congrats to me, I've done really well changing my lifestyle so that I'm eating well I've reversed my pre diabetes state, I'm fit, my cholesterol is down, Yay!!!!!!"Go me!!!!
A 5% weight loss of whatever weight you are can bring about vast health improvements. So even if you haven't reached a goal you have set this is a remarkable achievement. The other reason I am not sure setting goals in the context of weight loss is a good idea is that weight loss is one thing but keeping it off is often elusive. All the focus, attention and effort that might have gone into reaching this goal that we set have our selves is really difficult to maintain. While we have our eye on the prize we can create a script to follow. We can stick to it but after a while it becomes tedious and too rigid and inflexible. But worse, our body starts to have an argument with our mind. Our body starts to say I am hungry I need more food. Or we start out with such enthusiasm for exercise and restrictive eating in pursuit of our goal but realize we can't maintain the pace and our enthusiasm starts to fade. If you are a goal setting person, go for it by all means but if you are not, you most certainly haven't failed if you didn't reach your goals or if you didn't set any in the first place.