Weight loss, self-esteem, body image, depressive symptoms, and health related quality of life. These are the topics you can expect to read about in this article which covers the psychological aspects of weight loss.
The physical changes that occur when you lose weight are obvious. You get a healthier body, you lessen your chances for many heart and brain diseases, type two diabetes, cancer, and so on. The benefits are really many and have been talked about in great detail here and here.
However, as always, the psychological side of weight loss has been neglected. We have to understand that besides becoming healthier in the physical sense, most people undergo positive mental changes as well. And these are really important since you have to cope with your new self in a positive, productive, and healthy way.
Furthermore, I would like to point out another important point here. Weight loss is not accompanied just by positive physical and mental changes in our thinking patterns. People also consistently report that they feel better – their self-esteem, body image and quality of life improve just because they started eating healthier. That’s just another reason it’s something we should be striving for.
Thinking about the picture is important because it can improve our wholesome understanding of the effects of weight loss. It’s not just losing weight – you have to feel good in your new body and be able to keep up it as well. The latter two aspects are sometimes even more important because otherwise you can get unhealthy obsessions with your body (think bigorexia or orthorexia).
With that said, this is what has been gathered together in studies so far:
What is interesting about self-esteem is that it improves more when people lose weight by a change in behavior in comparison to different surgical procedures or the use of pills . By a change of behavior I mean different changes in eating patterns. This basically means it’s more likely your self-esteem will improve more if you lost your weight due to a lifestyle change or healthier eating, as opposed to undergoing surgery or using pills.
And the relationship between improved self-esteem and weight loss seems to be more or less linear, according to one study. It found out that the more weight you lose, the more your self-esteem will improve . This may seem quite self-explanatory and intuitive, but other studies didn’t notice this linear effect. Truth be told, it doesn’t even matter that much. All studies agree on improvements in self-esteem when you lose weight. In some of the studies, these outcomes could have happened by chance, but this was probably due to bad variable controlling and smaller sample sizes which are common in such studies. 
Out of seventeen studies, only one didn’t see a change in depressive symptoms when people lost weight . People reported feeling better (their depressive symptoms were reduced) when they lost weight in all the other studies. However, only three of them found a similar linear trend where those who lost more weight also reported feeling less depressed than others.
In others, it seemed to be more of a threshold type reduction. So after people lost a certain amount of weight, their depressive symptoms improved. 
This one may be quite self-explanatory to be honest. Studies so far have been consistently finding improvements in body image after people lost weight . Body image itself was usually measured either by someone’s body dissatisfaction, how high they rated their body on different scales (think from 1 to 10), their body shape concerns, body esteem, and others.
As you might imagine, improvements in body image were the highest among the three domains that I’ve mentioned so far – the biggest psychological improvement that you will notice among these three when you will lose weight is an increased satisfaction your body. 
Health-related quality of life
Health related quality of life can be described as your perception of your own physical, psychological, and social functioning in which you also include signs and symptoms of health and disease, as well as possible stigma you might notice for being overweight.
Studies have been noticing improvements in this domain as well. The highest improvements were usually found for a more specific measure – vitality. 
Health related quality of life is the aspect with the biggest connection to weight loss. By that I mean that your perceived health related quality of life is most closely tied to your weight loss. So health related quality of life improves even more than body image! When people lost 10% or more of their first bodyweight, there was a 5% (or more) improvement in the perceived quality of life. [6, 7]
Another interesting thing was found in one study, where people were reporting lower satisfaction with their social environment even though they were losing weight. This can be explained by the fact that they had a lot of social activities in their daily routine that were tied to (unhealthy) eating. And they had to pass up on this social eating when they started the intervention. What is even more interesting, the people from this study were very likely to regain their weight in later stages of the intervention. 
This only provides us with information on how strong the social part of weight loss is. It’s also something I have stressed a lot – sticking to lifestyle changes that you can abide by and not creating artificial momentary changes that you’ll most likely stop doing after a certain amount of time.
Wrap it up
To end – the psychological changes when you lose weight are immense. When you lose weight you become more satisfied with your body and your appearance in general. Your self-esteem improves, as well as your health related quality of life. In those who report different depressive symptoms, these improve as well with weight loss. And, as always, it’s important to stick to changes in eating that you can abide by – changes that negatively affect your current lifestyle will probably not last that long when it comes to weight loss.