Predictive Factors of Weight Loss in a Group of Obese Tunisian Women

Research Article

Austin J Endocrinol Diabetes. 2021; 8(2): 1087.

Predictive Factors of Weight Loss in a Group of Obese Tunisian Women

Abdesselem H1,2*, Harizi C2,3, Amor NB2,4, Mhidhi S2,4, Jamoussi H2,4, Sebai I1,2, Ounaissa K1,2, Fakhfakh R2,3 and Amrouche C1,2

1Outpatient Department and Functional Explorations, National Institute of Nutrition, Tunis, Tunisia

2University of Tunis EL Manar, Faculty of Medicine of Tunis, 1007, Tunisia

3Department of Epidemiology and Statistics, Abderrahmen Mami Hospital, Ariana, Tunisia

4Obesity Research Unit, UR18ES01, National Institute of Nutrition, Tunis, Tunisia

*Corresponding author: Abdesselem Abbassi Haifa, Outpatient Department and Functional Explorations, National Institute of Nutrition, Tunis, Tunisia; University of Tunis EL Manar, Faculty of Medicine of Tunis, 11 Djebel Lakhdar Street- Bab Saâdoun-Tunis, Tunisia

Received: August 09, 2021; Accepted: September 08, 2021; Published: September 15, 2021


Aim: The aim of this study was to identify the predictors of a weight loss of more than 5% of the baseline weight in a group of Tunisian women with obesity.

Methods: Prospective study at the Obesity Research Unit of the National Institute of Nutrition of Tunis, including 73 adult women with obesity. After 6 months of lifestyle interventions, univariate and multivariate logistic regression analysis were performed to extract predictors of success of weight loss at 6-months.

Results: More than half of patients (57.5%) achieved a loss of ≥5% of body weight from baseline. Univariate analysis found that initial weight loss at one month (p <10-3), potassium intake (p=0.010), phosphorus intake (p=0.012) and folate intake (p=0.025) were the factors associated with success of weight loss. The multivariate analysis showed that initial weight loss at one month (OR=2.369; p=0.02), TSH (OR=3.632; p=0.026) and dietary phosphorus intake (OR=0.995; p=0.011) were related to success of weight loss.

Conclusion: Larger-scale studies with long-term follow-up would be needed to better determine the predictors not only of success of weight loss but also of its long-term maintenance.

Keywords: Obesity; Weight loss; Dietetics


The rapidly growing prevalence of obesity has become a major public health due to the multitude of complications it can lead to and its cost for public health [1].

In Tunisia, in 2005, the overall prevalence of obesity in subjects aged between 35-70 years was 25.40% (13.3% in men and 37% in women). According to the results of the Tunisian Health Examination Survey 2016 (THES-2016), the overall prevalence of obesity was 26.2% (34.6% in women and 17.6% in men) [2].

Although there are many approaches to achieving weight loss, nutritional care remains the cornerstone in the treatment of people with obesity.

In addition to weight loss, the managing goals of people with obesity are to reduce the risk of comorbidities and to improve their quality of life. Several studies have shown that a modest weight loss of 5-10% of the baseline weight is reported to have significant positive effects on comorbid conditions [3,4]. Nevertheless, many patients undergoing lifestyle interventions do not reach this goal.

The aim of this study was to identify the predictors of a weight loss of more than 5% of the baseline weight in a group of Tunisian women with obesity.

Subjects and Methods

Study design and participants

We conducted a prospective study at the Obesity Research Unit of the National Institute of Nutrition and Food Technologies of Tunis (INNTA) between October 2016 and March 2018.

We included adult women with obesity, aged between 18 and 65 years, with a body mass index (BMI) ≥30Kg/m². We did not include secondary obesity, pregnant and breastfeeding women as well as women using one or more drugs that may interfere with energy metabolism such as corticosteroids, neuroleptics.

Data collection

At baseline, we measured the anthropometric parameters (weight, height, BMI, Waist Circumference (WC) and impedancemetry) of all the women included.

We used the World Health Organization (WHO) classification of obesity: obesity class I (BMI = 30-34.9 Kg/m²), obesity class II (35-39.9 kg/m²) and obesity class III (BMI ≥40kg/m²) [5] and the standards of the International Diabetes Federation (IDF) in the Mediterranean population to define abdominal or visceral obesity, defined by a WC ≥80cm [6].

Physical activity was assessed using a simplified semi-quantitative questionnaire from the INNTA standard used for the screening and management of overweight and obesity in adults. Three levels of physical activity have been identified: high, medium or low.

A nutritional survey, using the software “NUTRISOFT, version 2.01, 1988”, was conducted for all patients. Micronutrient intakes were assessed with reference to the nutritional intakes recommended by France’s Food Safety Authority, the AFSSA in 2011.

Women included in the study have benefited from a psychological assessment.

A biological assessment was carried out on the day of recruitment of the patients, including Fasting Plasma Glucose (FPG), 75g Oral Glucose Tolerance Test (OGTT), uric acid dosage, TSH, Total Cholesterol (TC), Triglycerides (TG), HDL-Cholesterol (HDL-C). LDL cholesterol was calculated according to the FRIDEWALD formula: LDL-C (g/l) = [TC - HDL - TG/2.2 in mmol/l] × 0.387).


The intervention aimed to encourage women with obesity to reduce or normalize their eating habits and to increase their physical activity.

All patients received personalized and adequate nutritional care involving a doctor, a nutritionist and a psychologist for 6 months. They benefited from personalized nutritional advice such as:

• Reduce total caloric intake

• Avoid very restrictive diets

• Divide the food intake into 3 main meals and a possible snack

• Respect the recommended intakes of the various macronutrients, favor the consumption of carbohydrates with low or medium glycemic index and limit those with high glycemic index.

• Limit the consumption of foods with high energy density, rich in lipids or sugars, limit the consumption of saturated and trans fats.

• Greater consumption of n-3 polyunsaturated fats

• Ensure a sufficient intake of dietary fiber (25-30 g/day), favor the consumption of vegetables and fruits.

• Drink enough water by limiting the consumption of sugary and alcoholic drinks.

• Diversify the diet based on equivalences and eat at set times, slowly, in a seated position.

For physical activity, all patients were advised to exercise moderate physical activity such as walking (30 to 60 minutes) daily or sports according to their choices. They were also advised to decrease sedentary activities such as sitting or lying down while watching television, sitting while driving a vehicle, sitting or lying down to read, or work at a desk or computer.

The psychologist accompanied the patients throughout their treatment by assessing emotional, socio-professional state and psychological problems that can impair the effectiveness of lifestyle intervention program, and looking for psychological factors that could promote eating disorders and/or resistance to treatment. Some patients have benefited from behavioral psychotherapy sessions when it was necessary.


We followed patients for 6 months with one follow-up visit per month. At each visit, anthropometric parameters were recorded, compliance with the dietary advice given during the first consultation were verified and corrections of any dietary errors were performed.

At the end of follow-up, we divided the patients into 2 groups according to the percentage of weight loss at 6 months in order to determine the predictive factors of success of weight loss:

Group 1 (G1): Women who lost ≥5% of baseline weight

Group 2 (G2): Women who lost <5% of baseline weight

Statistical methods

Data analysis was performed using SPSS 22.0. We calculated counts and percentages for the qualitative variables. Quantitative variables were expressed as means and Standard Deviations (SD).

A chi-square or Fisher’s exact test were used to compare between the two independent groups: patients who achieved weight loss ≥5% of baseline weight, and those who did not achieve this goal. Student’s t test was used to test the association between a qualitative variable and a quantitative one. In all statistical tests, the significance level was set at 0.05.

In order to identify the factors independently linked to weight loss, we conducted a multivariate analysis using logistic regression, taking as dependent variable the success of weight loss (≥5% of the initial weight) and as covariates the variables with univariate analysis test <0.2. The final returned variables were those significant at the level of 5%. Odds Ratio (OR) was presented with 95% Confidence Intervals (CI).

Ethical considerations

The study was conducted in accordance with the Declaration of Helsinki, after adequate understanding and written consent obtained from all the participants. Data confidentiality was respected.

Declarations of interest: none.


General patient characteristics are summarized in Table 1.