An interventional study of High-protein diet and resistance training and Balanced control diet in Obesity (Body Mass Index >30 kg/m2), sponsored by Norwegian University of Science and Technology. Active, not recruiting at 1 site in Norway. Open to participants aged 18 Years to 50 Years. Per ClinicalTrials.gov, last updated 2026-01-30.
Sponsored by Norwegian University of Science and Technology · Not applicable, Interventional, and Treatment
This clinical trial investigates whether a high-protein diet combined with resistance training is more effective than a standard low-calorie diet for maintaining fat mass loss in individuals with obesity.
A total of 60 adults with obesity (BMI ≥30 kg/m²) will be randomly assigned at baseline to one of two groups:
All participants will follow their assigned low-energy diets for the first 10 weeks, which constitutes the weight loss phase. The subsequent 42 weeks comprise the weight maintenance phase, where participants will follow an energy-balanced diet adapted to their individual needs and continue in their assigned group.
The intervention group will also complete supervised resistance training three times per week during the first 10 weeks, with continued follow-up throughout the maintenance phase.
Assessments will take place at baseline, week 11, 6 months, and 12 months, and include measurements of fat and lean mass, resting metabolic rate, appetite hormones, glucose metabolism, inflammation, gut microbiota and its metabolites, hedonic appetite, eating behavior, and quality of life and physical function. Participants will also provide food intake records, physical activity dat.
The primary aim is to determine whether the combined high-protein diet and resistance training intervention results in greater long-term fat mass loss and muscle mass preservation than the control diet. Secondary aims include effects on appetite regulation, eating behavior, metabolic health, and patient-reported outcomes.
The study is conducted at NTNU and St. Olavs Hospital in Trondheim, Norway, and registered under the acronym PRO-FIT.
6,296 studies on the registry are indexed under Obesity; 1,692 are open to participants now.
This study's planned enrollment of 60 is below the median of 78 across 4,878 interventional studies indexed under Obesity.
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Exclusion Criteria:
Intervention group: Participants will undergo a low-calorie high-protein diet for 10 weeks, followed by a maintenance phase up to the 1-year mark. This group will also participate in supervised resistance training sessions.
Other: High-protein diet and resistance training
Control group: Participants will undergo a balanced low-calorie diet for 10 weeks, followed by a maintenance phase up to the 1-year mark. This group will not receive any active exercise intervention.
Other: Balanced control diet
Participants will consume a low-energy high-protein diet for 10 weeks, and participate in supervised resistance training sessions. They will continue a maintenance diet up until the 1 year mark, with bi-monthly follow ups on diet and exercise.
Participants will consume a balanced low-energy diet for 10 weeks, and continue a balanced maintenance diet with bi-monthly follow ups up until the 1-year mark No active exercise intervention.
Fat-mass
Fat-mass will be estimated using a dual-energy absorptiometry (DXA, GE Healthcare Lunar).
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
Fat-free mass
Fat-free mass will be estimated using a dual-energy absorptiometry (DXA, GE Healthcare Lunar).
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
Body weight and -composition
Body weight and -composition will be estimated with dual-energy absorptiometry (DXA, GE Healthcare Lunar) (primary outcomes) and bioimpedance (InBody 770). Compartments that will be estimated are: total body weight, Fat-mass, fat-free mass, bone mineral density, visceral fat, muscle mass, body water, as well as segmental analysis of body weight and composition.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, 26 and at 52 weeks.
Anthropometric variables
Height, hip- and waist circumference will be measured using standardized methods. Body weight and height will be used to calculate body mass index in kg/m\^2. Hip-, waist- and height measurements will be used to calculate height/waist- and hip/waist ratio.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, 26 and at 52 weeks.
Resting metabolic rate
Resting metabolic rate will be measured in the fasted state using an indirect calorimetry (Quark RMR, Cosmed).
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
Leeds food preference questionnaire
Food reward and -preferences will be assessed with the Leeds Food Preference Questionnaire (LFPQ), in the fasted state and immediately after the test meal. The LFPQ is a computerized behavioral task that provides measures of 'explicit liking' and explicit and 'implicit wanting' for sensory and nutrient dimensions of foods using food images.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
Dutch Eating Behavior Questionnaire
The Dutch Eating Behavior Questionnaire measures restrained, external and emotional eating. Emotional eating can be divided into two sub-categories: diffuse emotions and clearly labelled emotions. The greater score, the greater external/emotional eating.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 26 and 52 weeks.
Power of Food Scale
The Power of food scale is a psychometric evaluation that measures an individual's preoccupation with wanting of highly palatable foods. The PFS consists of a 15-item list that measures hedonic hunger (food-related thoughts that are unrelated to homeostatic need). The higher the PFS score, the greater the hedonic hunger.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 26 and 52 weeks.
Three Factor Eating Questionnaire
The Three Factor Eating Questionnaire measures three different dimensions: restraint, disinhibition, and hunger. The greater score, the stronger is the trait/behavior.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 26 and 52 weeks.
Ghrelin
Blood will be collected in the fasted state (minute 0), and then at intervals after a standardized breakfast (minute 15, 30, 45, 60, 90, 120 and 150) and analyzed for acylated ghrelin concentrations.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
GLP-1
Blood will be collected in the fasted state (minute 0), and then at intervals after a standardized breakfast (minute 15, 30, 45, 60, 90, 120 and 150) and analyzed for total GLP-1 concentrations.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
CCK
Blood will be collected in the fasted state (minute 0), and then at intervals after a standardized breakfast (minute 15, 30, 45, 60, 90, 120 and 150) and analyzed for CCK concentrations.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
PYY
Blood will be collected in the fasted state (minute 0), and then at intervals after a standardized breakfast (minute 15, 30, 45, 60, 90, 120 and 150) and analyzed for total PYY concentrations.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
Insulin
Blood will be collected in the fasted state (minute 0), and then at intervals after a standardized breakfast (minute 15, 30, 45, 60, 90, 120 and 150) and analyzed for insulin concentrations.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
C-peptide
Blood will be collected in the fasted state (minute 0), and then at intervals after a standardized breakfast (minute 15, 30, 45, 60, 90, 120 and 150) and analyzed for c-peptide concentrations.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
Glucose
Blood will be collected in the fasted state (minute 0), and then at intervals after a standardized breakfast (minute 15, 30, 45, 60, 90, 120 and 150) and analyzed for glucose concentrations.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
GIP
Blood will be collected in the fasted state (minute 0), and then at intervals after a standardized breakfast (minute 15, 30, 45, 60, 90, 120 and 150). Plasma samples will be stored and analyzed for GIP concentrations depending on additional funding.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
Glucagon
Blood will be collected in the fasted state (minute 0), and then at intervals after a standardized breakfast (minute 15, 30, 45, 60, 90, 120 and 150). Plasma samples will be stored and analyzed for glucagon concentrations depending on additional funding.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
IL-6
Blood will be collected and plasma samples will be stored and analyzed for IL-6 concentrations depending on additional funding.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
TNF-alfa
Blood will be collected and plasma samples will be stored and analyzed for TNF-alfa concentrations depending on additional funding.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
CRP
Blood will be collected in the fasted state (minute 0), and analyzed for CRP.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
Triglycerides
Blood will be collected in the fasted state (minute 0), and analyzed for triglycerides.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
HbA1C
Blood will be collected in the fasted state (minute 0), and analyzed for HbA1C
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
HDL
Blood will be collected in the fasted state (minute 0), and analyzed for high-density lipoprotein
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
LDL
Blood will be collected in the fasted state (minute 0), and analyzed for low-density lipoprotein
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
Total cholesterol
Blood will be collected in the fasted state (minute 0), and analyzed for total choesterol.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
Hemoglobin
Blood will be collected in the fasted state (minute 0), and analyzed for hemoglobin.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
Gut microbiota
Fecal samples will be collected and comprehensive microbiota profiling using DNA-based sequencing will be performed.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
Short-chain fatty-acids
Fecal samples will be collected and acetate, propionate, and butyrate will be quantified by gas chromatography-mass spectrometry (GC-MS)
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
IWQOL-lite
The Impact of Weight on Quality of Life (IWQOL)-Lite questionnaire will be used to assess obesity-specific quality of life and includes 5 subcategories: physical function, self-compassion, sexual life, public distress and work. In addition, the total quality of life score will be assessed. Higher score, better quality of life.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
Short Form-36 (SF-36)
The SF-36, or Short Form 36, is a 36-item questionnaire used to assess a person's self-reported health-related quality of life. It measures eight health concepts: physical functioning, role limitations due to physical health, bodily pain, general health, vitality, social functioning, role limitations due to emotional health, and mental health where a higher score represents better health.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
Estimated one-repetition maximum (1RM)
1RM will be calculated using submaximal lifts performed to muscular failure within 4-8 repetitions.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 26- and 52 weeks.
Patient specific functional Scale
The Patient Specific Functional Scale is a patient-specific instrument. This means that the patient selects activities (three to five) that they have difficulty performing due to their illness or injury, and then rates their ability to perform these activities.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
Force development- and peak force
A one-repetition max tests and a force development- and peak force task will be undertaken on a force platform (Kistler, Switzerland) installed on a leg press device.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
Subjective appetite
Subjective ratings of appetite (hunger, fullness, desire to eat, and prospective food consumption) will be measured in fasting (minute 0) and then at minute 15, 30, 60, 90, 120 and 150 after the standardized test meal.
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
Blood pressure
Blood pressure will be measured in units of millimeters of mercury (mmHg)
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
Food records
Participants will quantify their daily energy intake by logging self-reported food diaries. Energy intake and macronutrient distribution will be calculated based on reported foods and quantitates.
Time frame: Before start of intervention, during weight loss phase, at 6 month follow up, and prior to assessments at week 52.
Ketone bodies
In addition to food logs, ketone bodies will be measured for compliance to diet and to account for potential nutritional induced ketosis. Acetoacetate will be measured in urine using Bayer ketostix and betahydroxtbutyrate using a freestyle libre ketone meter.
Time frame: At baseline assessments, during weight loss phase( baseline to week 11), at week 11 assessments, at 6 months and assessments at week 52
Plasma samples
Plasma samples will also be stored for exploratory analyses later
Time frame: From enrollment at baseline , after 10 weeks of weight loss phase, and at 52 weeks.
Adherence to exercise intervention
Attendance to scheduled training sessions will be recorded, together with type of exercise, sets, reps and loads.
Time frame: During weight loss phase( baseline to week 11), and during maintenance phase up until week 52
Physical activity levels
Physical activity levels will be estimated using actigraphs for 7-day periods.
Time frame: Before and during weight loss phase( baseline to week 11), at 26 and 52 weeks
Plan to share: Undecided
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Norwegian University of Science and Technology