Effect of a High-Protein Diet With Meal Replacements on Weight Loss

Evaluation of the Effectiveness of a High-Protein Diet With Meal Replacement and Dietary Supplementation in a Weight Management Program

The goal of this clinical trial is to learn if a structured high-protein diet with meal replacements can help with weight loss in adults with overweight or obesity. The main questions it aims to answer are:

Does this diet help participants lose more body weight? Does this diet improve body composition and blood markers such as glucose and cholesterol?

Researchers will compare a structured diet program with meal replacements to a standard low-calorie diet to see if it leads to better weight loss and health outcomes.

Participants will:

Follow a calorie-restricted diet for the duration of the study Be assigned to either a meal replacement program or a standard diet Attend study visits for body measurements and blood tests Report their feelings of hunger and fullness

Study Overview

• Status: Active, not recruiting
• Conditions: Obesity & Overweight
• Intervention / Treatment: Dietary supplement: Meal Replacement and Dietary Supplementation; Behavioral: Calorie-Restricted Diet

Detailed Description

This randomized, controlled clinical trial is designed to evaluate the effectiveness of a structured, high-protein, calorie-restricted diet that includes standardized protein-based meal replacement products and additional dietary supplements in capsule form compared to a standard low-calorie diet in adults with overweight or obesity.

Approximately 60 participants aged 25 to 60 years will be enrolled and randomly assigned to one of two groups. The intervention group will follow a structured nutrition program that includes replacing two main meals per day with a protein-based meal replacement shake and taking additional dietary supplements in capsule form twice daily with snacks. The control group will follow a conventional calorie-restricted diet based on general nutritional recommendations without meal replacement products or additional dietary supplements.

Participants in both groups will follow individualized meal plans tailored to their caloric needs.

Daily energy intake in both groups will be approximately 1400-1600 kcal, with an estimated energy deficit of about 500 kcal. Protein intake is expected to be higher in the intervention group compared to the control group.

The primary outcomes of the study include changes in body weight, body mass index, and body composition assessed by bioimpedance analysis. Secondary outcomes include metabolic parameters such as glucose, insulin, and lipid profile, as well as subjective measures including hunger, satiety, and overall well-being.

Participants will attend scheduled visits for anthropometric measurements and laboratory testing. Safety will be monitored throughout the study, including vital signs and the recording of any adverse events.

• Study Type: Interventional
• Enrollment (Actual): 60
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Kazakhstan
  • Almaty, Kazakhstan, 050010
    • Kazakh Academy of Nutrition LLP

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Adults aged 25 to 60 years
• Overweight or obesity
• Ability to provide informed consent
• Willingness to follow a calorie-restricted diet program
• Willingness to comply with study procedures

Exclusion Criteria:

• Pregnancy or breastfeeding
• Women of reproductive potential who are not using reliable contraception during the study
• Severe or uncontrolled cardiovascular disease, including recent myocardial infarction or stroke within the past 6 months, unstable angina, or heart failure
• Uncontrolled arterial hypertension at screening
• Severe renal impairment
• Severe hepatic dysfunction
• Diabetes requiring insulin therapy or uncontrolled diabetes
• Active oncological disease or cancer treatment within the past 12 months
• Acute or chronic inflammatory disease in the acute stage
• History of gastrointestinal or bariatric surgery affecting absorption or body weight within the past 12 months
• Severe pulmonary disease in the stage of decompensation Allergy or intolerance to components of the study products, including milk proteins or lactose-containing products Current use of medications or dietary supplements that significantly affect body weight, if discontinuation before study start is not possible Participation in another interventional clinical study within the past 3 months Inability to provide informed consent or comply with the study protocol Significant body weight change, defined as more than 5% gain or loss, within the past 3 months before screening Severe psychiatric disorders or eating disorders that may interfere with participation Active alcohol or substance dependence Chronic use of systemic glucocorticoids or other medications affecting body weight, if discontinuation is not appropriate Planned pregnancy during the study period Uncontrolled thyroid disease Acute infection or febrile illness at screening Clinically significant abnormal laboratory findings at screening that, in the investigator's opinion, make participation unsafe

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: High-Protein Diet with Meal Replacements; Participants follow a structured, calorie-restricted, high-protein diet that includes replacing two main meals per day with a protein-based meal replacement shake and taking additional dietary supplements in capsule form twice daily with snacks. Participants also receive individualized meal plans tailored to their caloric needs.	Dietary supplement: Meal Replacement and Dietary Supplementation; Participants replace two main meals per day with a protein-based meal replacement shake and take additional dietary supplements in capsule form twice daily with snacks as part of a structured, calorie-restricted diet. Participants also follow individualized meal plans tailored to their caloric needs.
Active Comparator: Standard Low-Calorie Diet; Participants follow a standard calorie-restricted diet based on general nutritional recommendations without meal replacement products. Participants also receive individualized meal plans tailored to their caloric needs.	Behavioral: Calorie-Restricted Diet; Participants follow a standard calorie-restricted diet based on general nutritional recommendations without meal replacement products or additional dietary supplements. Participants also follow individualized meal plans tailored to their caloric needs.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in body weight (kg)	Change in body weight measured in kilograms. Body weight will be assessed at baseline and monthly during the study	Baseline to 3 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in body fat percentage (%)	Change in body fat percentage measured by bioimpedance analysis. Assessments will be performed at baseline and monthly during the study	Baseline to 3 months
Change in lean body mass (kg)	Change in lean body mass measured by bioimpedance analysis. Assessments will be performed at baseline and monthly during the study	Baseline to 3 months
Change in body mass index (BMI, kg/m²)	Change in body mass index calculated as weight in kilograms divided by height in meters squared. Assessments will be performed at baseline and monthly during the study	Baseline to 3 months
Change in blood glucose concentration (mmol/L)	Change in fasting blood glucose concentration measured in mmol/L at baseline and at 3 months	Baseline to 3 months
Change in total cholesterol (mmol/L)	Change in total cholesterol levels measured in mmol/L at baseline and at 3 months	Baseline to 3 months
Change in LDL cholesterol (mmol/L)	Change in low-density lipoprotein (LDL) cholesterol levels measured in mmol/L at baseline and at 3 months	Baseline to 3 months
Change in HDL cholesterol (mmol/L)	Change in high-density lipoprotein (HDL) cholesterol levels measured in mmol/L at baseline and at 3 months	Baseline to 3 months
Change in triglycerides (mmol/L)	Change in triglyceride levels measured in mmol/L at baseline and at 3 months	Baseline to 3 months
Change in appetite-related scores assessed by Visual Analog Scale (VAS)	Change in self-reported appetite-related sensations assessed using a Visual Analog Scale (VAS), ranging from 0 to 10, where 0 indicates minimal intensity and 10 indicates maximal intensity of the measured sensation. The questionnaire includes multiple domains such as hunger, satiety, desire to eat, food intake capacity, food satisfaction, cravings, emotional influence on eating, and dietary control. Assessments will be performed at baseline and monthly during the study	Baseline to 3 months

Collaborators and Investigators

• Sponsor: Kazakh Academy of Nutrition
• Investigators: Study Director: Aliya Kaldybai, Kazakh Academy of Nutrition, Almaty, Kazakhstan

Study record dates

Study Major Dates

• Study Start (Actual): April 1, 2026
• Primary Completion (Estimated): July 1, 2026
• Study Completion (Estimated): July 1, 2026

Study Registration Dates

• First Submitted: April 17, 2026
• First Submitted That Met QC Criteria: April 17, 2026
• First Posted (Actual): April 23, 2026

Study Record Updates

• Last Update Posted (Actual): May 6, 2026
• Last Update Submitted That Met QC Criteria: April 29, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Randomized controlled trial; Weight loss; Body composition; Calorie restriction; Meal replacement; Dietary intervention; High-protein diet; Nutrition interventionMetabolic health
• Additional Relevant MeSH Terms: Nutrition Disorders; Overnutrition; Body Weight; Body Weight Changes; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Overweight; Obesity; Weight Loss; Therapeutics; Food; Diet, Food, and Nutrition; Physiological Phenomena; Food and Beverages; Nutritional Physiological Phenomena; Diet Therapy; Nutrition Therapy; Diet; Energy Intake; Dietary Supplements; Caloric Restriction
• Other Study ID Numbers: HPD15048; 15048 (Other Grant/Funding Number: Kazakh Academy of Nutrition)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data (IPD) will not be shared due to privacy and confidentiality considerations and the absence of a predefined data sharing plan.

Drug and device information, study documents

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