Acupuncture is an ADJUNCT therapy.
It is not a panacea or a wonder cure in the treatment of weight control. But, acupuncture is effective in making it easier to lose and maintain that loss if the patient is willing to change their lifestyle. The exact mechanism by which acupuncture works is unknown but we know that acupuncture needles inserted into specific points on the body and in the ear release endorphins which have a calming and relaxing effect that makes it easier to deal with stress, frustration and anxiety that can trigger overeating and bingeing on fattening foods. Also endorphins affect the digestive and hormonal systems so acupuncture can help rebalance the organ systems that are running too fast- or in this case too slow–i.e., the metabolism and the will power.

The Acupuncture Treatment
In order for the acupuncturist to choose the correct points for you, you must first come in for a consultation to discuss your particular pattern of overeating, and let the practitioner know in your intake form if there are any real digestive difficulties. Then the acupuncturist would check your pulse to discern the general state of your energy and measure the health of your stomach energy in particular, and then they would look at your tongue to check for cracks, peeling or puffiness on the stomach area, or a suspicious yellow or thick white coating that might indicate troublesome heat or coldness in the stomach and would provide some clues as to why the person was gaining weight.

The Acupuncture Points
Then, armed with this information, the acupuncturist would devise a treatment protocol using a combination of ear and body points. Although the Chinese developed the system of auricular (ear) acupuncture a long time ago, as one of the various Microsystems of the body containing all the points relating to the major organs and body parts, a Frenchman by the name of Nogier, discovered many more acupuncture points on the ear that pertain to Western medicine such as points called "Adrenal", "Pituitary", "FSH", "Ovary", "Thyroid", etc.
 
Many of the points from both ear acupuncture systems that are important for weight loss treatments are:
Mouth - for the impulsive eater who may also smoke a lot and talk a lot
Stomach - for the person who eats even after they're full or who's constantly nibbling
Hungry - for general appetite control
Lung - for food addicts, and people who love chocolate, sweets
Shenmen - a calming point, for the psychology overlay for anxiety, anger, frustration, insecurity
Endocrine - for water retention that's responsible for some of the weight gain
Adrenal and Ovary - if weight gain is due to menopause or P.M.S.
Spleen - for sugar imbalances and hormonal disturbances
Kidney - for water retention, and nervous system and hormonal imbalances
Thyroid - for slow metabolism

Next, body points would be selected.
During the first few treatments, most likely the "Four Gate" points (LI 4, Liver3) would be used to circulate the energy throughout the body and calm the nervous system. Ren 12, the front collecting point of the stomach energy would be chosen for many treatments, as would Stomach 36, three inches distal to the eye of the knee that tonifies the energy and helps circulate oxygen and blood of the whole body and of the stomach in particular. Then, based on the diagnosis, the practitioner may add Stomach, 40, the master point for mucous, or Kidney 7 or 10 for edema or water retention.