The investigators aims in the current study are to examine whether the cholinergic status should be considered as another risk factor for the metabolic syndrome and it's co-morbidities and to test the effect of a hypocaloric high complex carbohydrates diet on the cholinergic status of overweight and obese adults with and without the metabolic syndrome.

Intervention studies have demonstrated that the autonomic disturbances of the metabolic syndrome may be reversible. A reduction in body weight induced by a hypocaloric diet exerts a marked reduction in sympathetic activity in obese people with or without metabolic syndrome. Incorporation of regular, moderate intensity aerobic exercise training during a dietary weight loss program does not confer additional benefits on resting sympathetic neural activity, compared with weight loss by diet alone. A new method has been developed to examine the sympathetic-parasympathetic status of an individual - the cholinergic status. Cholinergic Status represents the total soluble circulation capacity for acetylcholine hydrolysis. Higher cholinergic status means the individual is more sympathetic .

A cross sectional study that took place in Tel Aviv Sorasky medical center and included 632 participants found that the cholinergic status is related to metabolic syndrome parameters in a dose response manner and that it correlates significantly with glucose,HbA1c, lipid profile and hs-CRP.

Inclusion Criteria:

• BMI ≥ 25kg/m2
• Stable weight (±1kg)in the previous six months
• Non smokers

Exclusion Criteria:

• Type II diabetes
• Hypertension pharmacologically treated
• Cardiovascular disease
• Renal disease
• Cirrhosis and end-stage liver failure
• Thyroid disease
• Cerebrovascular disease
• Cancer
• Autoimmune disease
• Chronic inflammatory disease
• Surgery or heart catheterization in the previous six months
• Use of drugs known to affect measured parameters