Diet, Imaging and Energy Balance Trial (DIET)

We propose a parallel arm randomized clinical trial of two diets-a low carbohydrate ketogenic diet (LCKD) and a low fat diet (LFD). Following screening, eligible participants will undergo a six week dietary intervention that will include 7 clinic visits at the Duke Lifestyle Medicine Clinic (Director: Dr. Westman). In addition to the dietary intervention, participants will undergo fMRI scanning on two occasions: once in the week prior to randomization to a diet (Baseline Scan) and after three weeks of following a diet (Post-Diet Scan). During scanning participants will view food cues in order to assess the effects of diet on brain responses to different macronutrient content categories (e.g., High vs. Low Complex Carbohydrate). In addition to scanning measures, we will also record information regarding dietary intake, food preferences, weight, mood, and diet adherence.

Inclusion criteria

Participants must be 18-50 years old, right handed and have a BMI > 27 kg/m². They must be willing to follow either of the two diets.

Exclusion criteria

• weigh over 300lbs.
• have uncontrolled hypertension (systolic >160mm Hg, diastolic >100mm Hg)
• have hypotension (systolic <90 mm Hg, diastolic <60 mm Hg)
• have coronary heart disease, or cardiac rhythm disorder
• cerebrovascular disease or peripheral vascular disease that requires intensive hyperlipidemic therapy
• other significant co-morbid illnesses such as liver disease (AST or ALT > 100), kidney disease (serum creatinine > 1.5), cancer, severe emphysema, severe hypertriglyceridemia (TG>500)
• have diabetes (insulin or diet controlled)
• have a current psychiatric disease
• have current alcohol abuse (greater than 12 drinks per week)
• have current drug abuse (or treatment within the last year)
• use of psychiatric medications (including antidepressants, anti-anxiety agents, anti-psychotics, "muscle relaxants" or any other drug that influences mood, cognition, or neurotransmitter systems, i.e. dopamine, norepinephrine, acetylcholine, serotonin, GABA, and glutamate)
• have had or have an eating disorder including anorexia nervosa, bulimia nervosa, eating disorder not otherwise specified, binge eating disorder, or any other form of disordered eating
• have had any bariatric/weight loss surgery
• be taking any diet pills (prescription or over the counter)
• have been on any diet in the last 3 months
• have any restrictive dietary requirements (including: vegetarians, vegans, or any other dietary restraints)
• have any food allergies
• be on an exclusively ethnic diet
• be females who are pregnant, nursing mothers or likely to become pregnant
• have any major medical condition that would make participation unsafe (e.g., have pacemaker or other metallic implant (including dental, orthopedic, or IUD), uncomfortable (e.g., chronic pain), confound results (e.g., psychiatric condition)
• be left handed
• have glaucoma, color blindness
• be using experimental or investigational drugs
• or suffering from claustrophobia