The Effects of Leucine on Body Weight

Protein-rich diets appear to show some benefits in promoting weight loss. It is thought that increased intake of leucine may account for some of this effect. This study is designed to assess whether any of the beneficial effects of dietary leucine supplementation observed in mice also apply to humans. Specifically, our team would like to determine whether oral leucine supplementation in overweight/obese humans increases metabolic rate, reduces body weight, improves glucose utilization and/or, reduces circulating fat levels in the blood. We hope that the results obtained from this pilot study will highlight the specific aspects of metabolic improvement associated with increased daily leucine intake. This study will should provide data that can be used to design more definitive trials with regard to dietary leucine supplementation. Hypothesis This pilot study is designed to accomplish the following two goals: to assess whether any of the beneficial effects of dietary leucine supplementation observed in mice also apply in humans. Specifically, we want to determine whether oral leucine supplementation in overweight/obese individuals' increases basal metabolic rate, reduces body weight, improves glucose tolerance and/or insulin sensitivity, and/or reduces circulating Low-density Lipoprotein (LDL)-cholesterol levels. To provide data that can be used to design more definitive trials with regard to dietary leucine supplementation. We hope that the results obtained from this pilot study will highlight the specific aspects of metabolic improvement associated with increased daily leucine intake. This would in turn lead to more rigorous clinical trials involving larger sample sizes, and with diverse populations of different gender, age, and ethnic groups. Future trials may also be directed to determine minimal doses and durations of leucine supplementation that are capable of achieving clinically significant improvement in the cardio-metabolic risk profile in people.

This will be a triple arm design where subjects will be randomized into three groups. Arm #1 will be 4g of Leucine.

Supplementation in the form of a liquid meal (premixed leucine powder solutions with flavor made by the Bionutrition Unit of the Irving Insitute for Clinical and Translational Research (IICTR)). Dosing of leucine will be a combination of 2 ounces of liquid per 1 gm of leucine. L-leucine was purchased (FCC quality) from Spectrum Chemical,California. Certificate of analysis enclosed (99.89% leucine).Liquid meal preparation: Grape juice and crystal light mixes will be used for the preparation of liquid meals that will be given to each participant each week. Participants will consume two 8 ounce drinks (packaged in two 10 ounce bottles) per day. Each drink will be individually prepared with 8 grams of leucine.

Liquid meal preparation (contents): Grape juice and crystal light mixes will be used for the preparation of liquid meals that will be given to each participant each week. Participants will consume two 8 ounce drinks (packaged in two 10 ounce bottles) per day. The placebo group will have the same drinks listed above with no leucine incorporated.

Supplementation in the form of a liquid meal (premixed leucine powder solutions with flavor made by the Bionutrition Unit of the Irving Insitute for Clinical and Translational Research (IICTR)). Dosing of leucine will be a combination of 2 ounces of liquid per 1 gm of leucine. L-leucine was purchased (FCC quality) from Spectrum Chemical,California. Certificate of analysis enclosed (99.89% leucine).Liquid meal preparation: Grape juice and crystal light mixes will be used for the preparation of liquid meals that will be given to each participant each week. Participants will consume two 8 ounce drinks (packaged in two 10 ounce bottles) per day. Each drink will be individually prepared with 4 grams of leucine.

Inclusion Criteria: 18-65 year old overweight/obese healthy men and women Body Mass Index (BMI) of 28-35 Exclusion Criteria: unusual or extreme dietary or exercise habits daily leucine supplement use inability to follow instructions to drink liquid meals type 1 diabetes or type 2 diabetes on drug treatment(diet controlled diabetics will be enrolled after consulting with their treating physicians) hypothyroidism or hyperthyroidism chronic wasting diseases (Acquired Immune Deficiency Syndrome (AIDS), cancers, cirrhosis, renal failure, Chronic Obstructive Pulmonary Disease (COPD), heart failure) drug or alcohol abuse tobacco smoker within the past 6 months pregnancy or lactating use of medications known to affect carbohydrate or lipid metabolism, satiety, or hunger anemia abnormal liver function tests (LFTs) women who are of child bearing age without adequate birth control modality