Diabetes
Hypertension
Elevated Cholesterol
Elevated Triglycerides
Heart Attack, Congestive Heart Failure
Cardiac Arrhythmias, Sudden Death
Stroke
Renal Failure
Pulmonary artery hypertension
Cor Pulmonale (right heart failure)

Pulmonary Complications

Lung Restriction
Shortness of Breath on Exertion
Decreased Exercise Tolerance
Asthma
Heavy Snoring
Obstructive Sleep Apnea

Malignancies

Breast
Prostate
Colon
Uterine lining (endometrium)

Other Medical Complications

Heartburn (GERD)
Joint and Back Pain
Accelerated Degenerative Joint Disease
Gallstone formation
Hormonal Abnormalities
Excess Estrogen
Abnormal Menstrual Cycle
Infertility
Excess Testosterone
Facial Hair
Acne
Stress Incontinence
Varicose Veins
Leg, ankle Swelling
Rashes, Skin Infections, Excess Sweating, Panniculitis (infected abdominal skin fold)
Pseudotumor Cerebri
Nephrotic Syndrome
Hernias
Increased risk of certain cancers
Steatohepatitis (fat induced hepatitis)
Hypercoagulable States
Pulmonary embolism
Accidents/Trauma
Gout

Psychosocial Complications

Lack of Self Esteem
Social Rejection
Loss of Job Potential
Inappropriate Coping Strategies
Depression
Anxiety


The good news is that most of these problems will improve as one loses weight through diet and exercise or through surgery such as gastric bypass. Even if irreversible damage has been done, such as joint breakdown, the damage will be easier to live with when one is lighter.