Here are some references by Scientific Experts on the use of Hypnosis for Weight Control: 

Dr. Mahmet Oz

“Hypnosis unlocks your subconscious power to control the demons that make you overeat.” 

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Cochrane, Gordon; Friesen, J. (1986). Hypnotherapy in weight loss treatment. Journal of Consulting and Clinical Psychology, 54, 489-492.
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Investigated the effects of hypnosis in weight loss for 60 females, at least 20% overweight. Treatment included group hypnosis with metaphors for ego-strengthening, decision making and motivation, ideomotor exploration in individual hypnosis, and group hypnosis with maintenance suggestions. Hypnosis was more effective than a control group: an average of 17 lbs lost by the hypnosis group vs. an average of 0.5 lbs lost by the control group, on follow-up.

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Journal of Consulting and Clinical Psychology (1985)
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109 people completed a behavioral treatment for weight management either with or without the addition of hypnosis. At the end of the 9-week program, both interventions resulted in significant weight reduction. At 8-month and 2-year follow-ups, the hypnosis subjects were found to have continued to lose significant weight, while those in the behavioral-treatment-only group showed little further change.  
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University of Connecticut, Storrs Allison DB, Faith MS. Hypnosis as an adjunct to cognitive-behavioral psychotherapy for obesity: a meta-analytic reappraisal. J Consult Clin Psychol. 1996;64(3):513-516.
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Researchers analyzed 18 studies comparing a cognitive behavioral therapy such as relaxation training, guided imagery, self monitoring, or goal setting with the same therapy supplemented by hypnosis.  Those who received the hypnosis lost more weight than 90 percent of those not receiving hypnosis and maintained the weight loss two years after treatment ended.

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Weight loss for women: studies of smokers and nonsmokers using hypnosis and multi-component treatments with and without overt aversion. Johnson DL, Psychology Reprints. 1997 Jun;80(3 Pt 1):931-3. .

Two studies compared overweight smoking and non-smoking adult women in an hypnosis-based, weight-loss program. Both achieved significant weight losses and decreases in Body Mass Index. Follow-up study replicated significant weight losses and declines in Body Mass Index. The overt aversion and hypnosis program yielded significantly lower post-treatment weights and a greater average number of pounds lost.

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University of Connecticut, Journal of Consulting and Clinical Psychology in 1996 (Vol. 64, No. 3, pgs 517-519)
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An analysis of five weight loss studies reported in the Journal of Consulting and Clinical Psychology in 1996 showed that the "… weight loss reported in the five studies indicates that hypnosis can more than double the effects" of traditional weight loss approaches.
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Journal of Consulting and Clinical Psychology (1996)

Research into cognitive-behavioral weight loss treatments established that weight loss is greater where hypnosis is utilized. It was also established that the benefits of hypnosis increase over time.
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Journal of Consulting and Clinical Psychology (1986)
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A study of 60 females who were at least 20% overweight and not involved in other treatment showed hypnosis is an effective way to lose weight.