Hypnosis is not what a lot of people think it is. People think it means you are out of it, and under the power of the hypnotist to do their bidding. It is not like that. Hypnosis is more a tool to get people into a deeply relaxed state of mind and body, and then in this relaxed state our mind, the even subconscious mind is more accepting of suggestions made to it. Because we are so relaxed, our defences and barriers are down, we do not fight suggestions, we just accept them. So, for this reason, it can be used to change some of thinking patterns, behaviours and associations we have.
There are not many studies done on weight loss and hypnosis, but there are a few. The short answer is – yes, if you do hypnosis as a part of a holistic plan with food, movement and mind therapies then it can mean you may lose more weight. One meta-analysis in 1996 showed a difference of about an extra 2.7kg over 18 months. Though I cannot find any studies looking at hypnosis by itself without doing the food, movement and mind changes we have already discussed.
From personal experience, not having seen any studies to support this, the people who seem to benefit the most are those who have certain difficult and negative behaviours with their food or strong associations. Associations mean that when we experience one thing, we immediately think or feel something else. The most common one is stress, when people feel stressed they automatically get feels of urges and cravings for sweet or fatty food. So the goal of hypnotherapy and any psychological or behaviour therapy is to decouple these two things. Next time you feel stress you don’t think of sugar or fat, but rather perhaps of fruit, or breathing, or walking, or art or something else. So hypnotherapy is one tool to help that restructuring your mind and behaviours. You definitely don’t have to do it, but if you do, it might help.