Intestinal Sweet Taste Receptor Function and Adaptation to Dietary Sugars and Sweeteners (ISTAR)

Inclusion Criteria:

1. Age 18-65 years inclusive;
2. Men and women;
3. Able to provide written, informed consent;
4. Weight stable (± 3 kg) during the 3 months prior to enrollment;
5. BMI ≤ 25 kg/m2

Exclusion Criteria:

1. Diagnosed with any of the following co-morbidities: a) coronary artery disease, angina or heart failure, b) diabetes, c) bleeding disorders, d) infections, e) hepatitis and/or cirrhosis, f) severe asthma or chronic obstructive pulmonary disorder, g) renal insufficiency, h) bariatric surgery, i) inflammatory bowel disease or malabsorption, j) cancer within the last 3 years (except non-melanoma skin cancer or treated cervical carcinoma in situ), k) psychiatric or eating disorders, l) untreated or inadequately controlled thyroid or other endocrine disorders, m) active rheumatoid arthritis or other inflammatory rheumatic disorder;
2. Consumption of more than a can of diet beverage or a spoonful of non-caloric artificial sweeteners weekly (or each equivalent from foods) during the past month.
3. Pregnant or nursing women;
4. Current smokers (smoking within the past 3 months);
5. Known hypersensitivity to saccharin, lactisole, and acetaminophen or any of its exipients;
6. History of difficult blood sample collections or unfavorable anatomy of venous access;
7. Use of medications: a) nitrates, b) beta-blockers, c) digoxin, d) anti-diabetic agents, e) oral, injected or chronic topical steroids (inhaled steroids for mild asthma are acceptable), f) chronic use of aspirin or other non-steroidal anti-inflammatory drugs, g) other drugs known to affect immune or metabolic function and h) orlistat, phentermine or other weight loss or anorectic agents.
8. Blood pressure greater than or equal to 160/100 or less than or equal to 100/50 at screening.