This study compares two types of diet interventions: a low carbohydrate ketogenic diet (Atkins) and a low-fat diet combined with a medication (Orlistat).

Overweight and obesity are increasingly prevalent in the veteran population as well as the general public. For patients with obesity-associated illnesses, there are few effective treatment options available after failed attempts at diet and exercise, even though weight loss has been shown to alleviate these conditions. The purpose of this study is to compare the tolerability, safety, and efficacy of a low-carbohydrate ketogenic diet (Atkins) with a combination of a low-fat diet and Orlistat. The outcomes examined over a 48 week duration will include body weight, risk factors for heart disease (e.g., lipid profiles), and blood sugar. This is a randomized, parallel-intervention trial. Subjects (n=150) will be recruited from the Durham VAMC Ambulatory Care Clinics. All patients receive one of the two intensive weight loss interventions.

Inclusion Criteria:

• Participants must have a VA medical center primary care provider;
• Failed first line diet and exercise recommendations;
• In stable health by screening physical and lab tests;
• Agrees to make regular visits per study protocol;
• Has access to telephone;
• Body mass index (BMI) > or = 27 with obesity-related illness OR BMI > or = 30 with no risk factors;
• No contraindications to Orlistat;
• Not pregnant or breast-feeding;
• No serious mental health illness such as dementia or schizophrenia;
• No use of a weight loss therapy in the month prior to screening.

Exclusion Criteria:

• No VAMC primary care provider
• Unable to attend regular study visits
• No access to telephone
• BMI < 27
• Contraindications to Orlistat
• Pregnancy, breast feeding or planning to become pregnant
• Unstable mental health illness
• Use of a weight loss therapy in the month prior to screening

160 participants were randomized (81 allocated to LCKD, 79 to Orlistat plus LFD). 14 did not receive the intervention. 33 discontinued the intervention. Out of the 146 participants analyzed, 113 completed the intervention.

48 weeks

The O + LFD participants reported gastrointestinal effects more frequently than the LCKD participants, occurring predominantly after dietary indiscretions. The LCKD had its own gastrointestinal adverse effect, constipation, in most cases resolving by increasing fluid and dietary fiber intake and/or adding a fiber supplement or stool softener.

We provided orlistat at no cost. This could have increased dietary adherence, attendance, and/or retention compared with the LCKD and may lead to different results than what might be seen in patients who must pay for orlistat.