Comparing a Low-GI Nutrigenetic and Ketogenic Diet for Weight Loss With 18 Month Follow-up (LOWGI_GENE)

The investigators followed a convenience sample of 114 overweight and obese subjects from a weight loss clinic who followed a 24-week dietary intervention. The subjects self-selected whether to follow a standardized ketogenic diet (n=53), or a personalised low-glycemic index (GI) diet utilising information from 28 single nucleotide polymorphisms (n=61). After the 24-week study period, the subjects were monitored for an additional 18 months.

Study Overview

• Status: Completed
• Conditions: Weight Loss; Glucose, High Blood; LDL Hyperlipoproteinemia; HDL; Triglycerides High
• Intervention / Treatment: Other: weight loss diets

Detailed Description

In the present study, the investigators followed patients in a clinic who self-selected either a ketogenic diet with no nutrigenetic modification, or a low glycemic index (GI) based diet with nutrigenetic modifications. The addition of nutrigenetic advice was not designed nor proposed to patients as a weight loss diet, nor to predict either disease risk or obesity risk; the aim was simply to optimize the nutrient content of an individual's daily food intake, based on current understanding of an individual's genetic profile. The aim of this study, therefore, was to compare the performance of the well-known, and generally the most effective in the short-term [25], ketogenic diet to a low-GI nutrigenetic diet. A ketogenic diet has also shown to have long-term (12 months) effectiveness for weight loss [26], although the effects of the diet over a longer time period than this are currently unclear.

114 overweight (n=1) and obese (n=113) subjects (M = 55, F = 59, age 24-56y, all of Romanian heritage and similar socio-economic status), who were patients at a weight management clinic (Bucharest, Romania), gave written informed consent for their weight loss data to be prospectively analysed for this study. All patient data were handled according to the Romanian Code of Medical Deontology and in accordance with the Helsinki Agreement. Approval was given by the Ethics Committee of the University and Pharmacy, Cluj Napoca, Romania (registration number 444). Upon enrolment at the weight management clinic, the subjects self-selected either a ketogenic diet or a low-GI nutrigenetic diet. A ketogenic diet was utilised as the comparison diet due to its reported efficacy in the treatment of obesity [26]. Fifty-three subjects (25 female; age 43.0 ± 7.2y) selected the ketogenic diet plan, and 61 subjects (34 female; age 42.0 ± 6.7y) selected the low-GI nutrigenetic diet plan. Subjects in the low-GI nutrigenetic diet group underwent DNA testing (NutriGENE by Eurogenetica Ltd/DNAfit, UK) for 28 Single Nucleotide Polymorphisms (SNPs) in 22 genes with good evidence of gene-diet/lifestyle interactions [table 1]. Overall participation in both diet groups cost a similar amount, comprised of approximately €300 for the genetic test along with 1-month diet plan, initial evaluation, body composition, and medical history for the nutrigenetic group, and €280 for the ketogenic group, providing Ketostix and the same evaluations. Further visits through the 24-week program the overall cost per patient was approximately €800. After 24 weeks diet follow up visits had no further cost.

After the 24-week study period, the subjects were monitored for an additional 18 months.

At the study onset, patients were not type 1 or type 2 diabetics, although many were hyperglycemic, which is a common issue in obese subjects. Any patients with records of any other disease were excluded prior to commencing the dietary intervention. The patients, apart from obesity, were otherwise "healthy".

• Study Type: Observational
• Enrollment (Actual): 114

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 24 years to 56 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Probability Sample

Study Population

114 overweight (n=1) and obese (n=113) subjects (M = 55, F = 59, age 24-56y, all of Romanian heritage and similar socio-economic status

Description

Inclusion Criteria:

• Obese (BMI ≥30)
• Age ≥ 18 years
• Male or female
• Smoking or not smoking

Exclusion Criteria:

• Type 1 diabetes
• Type 2 diabetes
• Any other disease

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Retrospective

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
LowGI/nutrigenetic; 114 overweight (n=1) and obese (n=113) subjects (M = 55, F = 59, age 24-56y, all of Romanian heritage and similar socio-economic status), who were patients at a weight management clinic (Bucharest, Romania), gave written informed consent for their weight loss data to be prospectively analysed for this study. Upon enrolment at the weight management clinic, the subjects self-selected either a ketogenic diet or a low-GI nutrigenetic diet. 61 subjects (34 female; age 42.0 ± 6.7y) selected the low-GI nutrigenetic diet plan.	Other: weight loss diets; The ketogenic diet group were instructed to consume <35g of carbohydrates per day, and <10% of total calories were from saturated fats. Daily protein intake was set at 1.2g/kg bodyweight for females, and 1.5g/kg bodyweight for males. The low-GI nutrigenetic diet group had individualised dietary instructions based on their genetic results
Ketogenic; As above + Fifty-three subjects (25 female; age 43.0 ± 7.2y) selected the ketogenic diet plan	Other: weight loss diets; The ketogenic diet group were instructed to consume <35g of carbohydrates per day, and <10% of total calories were from saturated fats. Daily protein intake was set at 1.2g/kg bodyweight for females, and 1.5g/kg bodyweight for males. The low-GI nutrigenetic diet group had individualised dietary instructions based on their genetic results

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Weight loss - kg and BMI	Weight loss after 6 months diet	6 months
Weight loss - kg and BMI	After 18-months follow up on normal nutrition	18 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Blood glucose	Levels of blood glucose	6 months
Blood glucose	Levels of blood glucose	18 months
Cholesterol	Levels of LDL and LDL	6 months
Cholesterol	Levels of LDL and LDL	18 months
Triglycerides	Levels of blood triglycerides	6 months
Triglycerides	Levels of blood triglycerides	18 months

Collaborators and Investigators

• Sponsor: Iuliu Hatieganu University of Medicine and Pharmacy

Publications and helpful links

General Publications

• Vranceanu M, Pickering C, Filip L, Pralea IE, Sundaram S, Al-Saleh A, Popa DS, Grimaldi KA. A comparison of a ketogenic diet with a LowGI/nutrigenetic diet over 6 months for weight loss and 18-month follow-up. BMC Nutr. 2020 Sep 24;6:53. doi: 10.1186/s40795-020-00370-7. eCollection 2020.

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2014
• Primary Completion (Actual): December 31, 2016
• Study Completion (Actual): June 1, 2017

Study Registration Dates

• First Submitted: March 27, 2020
• First Submitted That Met QC Criteria: March 31, 2020
• First Posted (Actual): April 1, 2020

Study Record Updates

• Last Update Posted (Actual): April 8, 2020
• Last Update Submitted That Met QC Criteria: April 6, 2020
• Last Verified: April 1, 2020

More Information

Terms related to this study

• Keywords: weight loss; ketogenic; Glycaemic index; nutrigenetics; nutrigenomics
• Additional Relevant MeSH Terms: Metabolic Diseases; Body Weight Changes; Lipid Metabolism Disorders; Dyslipidemias; Weight Loss; Body Weight; Hyperlipidemias; Hyperlipoproteinemias
• Other Study ID Numbers: LOWGI_GENE

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Undecided
• IPD Plan Description: genetic, weight, gender, age, blood biomarker data

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No