A systematic review of randomized controlled trials of dietary interventions for weight loss in adults in the Middle East and north Africa region

Summary The prevalence and incidence of obesity, and associated complications, such as type 2 diabetes, in the Middle East and north Africa (MENA) region rank among the highest in the world. Little is known about the effectiveness of dietary weight loss interventions conducted in the MENA region. We conducted a systematic review of randomized clinical trials aiming to assess the effectiveness of dietary interventions for weight loss in the adult population originating from and residing in the MENA region. In accordance with PRISMA guidelines, PubMed, CINAHL, Cochrane, and EMBASE were systematically searched for randomized controlled trials (RCT) using dietary interventions for weight loss conducted in the MENA region. RCTs examining weight loss as an outcome in adults (≥ 18 years old) were included. The Cochrane Collaboration tool for assessing risk of bias was used to ascertain the quality of the eligible RCTs and the Template for Intervention Description and Replication for population health and policy interventions (TIDieR‐PHP) checklist was used to evaluate the reporting of the interventions. Twenty‐nine RCTs including 2792 adults from five countries in the MENA region met the search criteria. Study participants were predominantly middle‐aged females. Duration of follow up was mostly 3 months or less. Weight loss ranged from −0.7 to 16 kg across all intervention groups and the average weight loss was 4.8 kg. There was paucity of description of the weight loss interventions and variations amongst studies did not allow a meta‐analysis of findings. It was not possible to draw firm conclusions on the effectiveness of dietary weight loss interventions in the region. High quality studies using more structured interventions of longer duration with standardized outcome measures are needed in the MENA region to support clinical practice with evidence‐based interventions for obesity.


| INTRODUCTION
Obesity is a significant global health problem affecting developed and developing countries alike. The prevalence of obesity over the past few decades has more than doubled resulting in about one third of the population having a body mass index (BMI) in the obese range. 1 The rise in obesity prevalence has occurred across all age groups, geographical locations, and socioeconomic categories. 1 The Middle East and north Africa (MENA) region is experiencing a significant challenge from population obesity and diabetes. A systematic review estimated that 25% to 82% of adults (with higher prevalence in women) and 7% to 45% of school children in the MENA region were within overweight or obese range. 2 Another study compared the prevalence of obesity in 52 countries across eight different geographical locations, and found that women in the MENA region had the highest waist-to-hip ratio and the second highest BMI, after United States, compared to other regions. 3 Similar findings were reported by another study that included 199 countries. 4 Obesity is a key risk factor for non-communicable diseases (NCD), such as cardiovascular disease (CVD), 5 type 2 diabetes mellitus (T2DM), 6 chronic kidney disease, 7 several major cancers, 8 musculoskeletal disease 9 and mental health disorders. 10 The rapid rise of obesity prevalence has led to a substantial increase in the prevalence of NCD in the MENA region, particularly at a younger age. 2 The International Diabetes Federation (IDF) estimated that in 2017, 40 million people were living with diabetes in the MENA region and projected that this number will more than double to 86 million in 2045, 11 placing the region as having the second highest prevalence of diabetes identify key interventions (and assess their effectiveness) that may inform guidelines for prevention and treatment of obesity in the region. Furthermore, our systematic review aimed to identify research gaps for tackling obesity in a region with one of the highest prevalence of obesity.

| Protocol and Registration
This systematic review was conducted according to the PRISMA guidelines, 13 and used a pre-defined protocol registered with PROS-PERO (CRD42017068811). The full systematic review described in the protocol evaluates all randomized controlled trials (RCTs) of dietary interventions conducted in the MENA region. For the purposes of this report, the focus was on interventions for adults. Furthermore, the current report does not address the use of dietary supplements.
For a more comprehensive review, studies that reported changes in weight as an outcome measure were included.

| Participants
All studies carried out in adults (≥ 18 years old) were included. Participants had to originate from the MENA region, which was defined to include the following countries: Algeria, Bahrain, Cyprus, Egypt, Iran, Iraq, Israel, Jordan, Kuwait, Lebanon, Morocco, Oman, Palestine, Qatar, Saudi Arabia, Somalia, Sudan, Syria, Tunisia, Turkey, United Arab Emirates and Yemen.

| Interventions
All studies using dietary interventions with the aim of, or reporting, weight loss as a key outcome were included. Any intervention that used any medicinal products, surgical interventions, or nutritional supplements for weight loss were excluded. No filter on the duration of intervention was placed.

| Types of comparators
Included studies all had comparator groups. This included comparison with no intervention or comparison between various intervention modalities.

| Type of outcome measures
Included studies had to report on weight or weight loss (measured in kilograms or change in BMI) as an outcome. This had to be measured at baseline and then at least one time point from baseline. Outcomes reflecting glycaemic control were of secondary interest in this review and are included if reported in publications.

| Types of studies
Only RCTs were considered for inclusion.

| Study selection
The inclusion and exclusion criteria are listed in Table 1

| Information sources
The search strategy and terms were developed by the research team.
Studies were identified by searching the following electronic databases: PubMed, Medline, CINAHL, Cochrane, and EMBASE. Databases were searched from inception to February 2020. Search terms (keywords, subject headings, and so on) applicable to the subject areas of "diet" and "Middle East" and "north Africa", as defined in this systematic review, were used and also harvested from within the content of the databases listed above. The search terms were reviewed by several authors and are provided in additional file on request; both subject headings and keywords were used in search string construction. Boolean Operators and truncation were inserted into searches at all points in which these functions were seen as an appropriate enhancement to a search. The search string used is available in the supplementary material.
No filters for language or years of publication were applied to the searches. Searches within the grey literature were conducted in order to harvest relevant works that might not be uncovered through only searching through the contents of traditional scholarly databases.
Finally, a manual search was performed by two independent reviewers to retrieve any articles that were not identified in the initial search. The reference lists of relevant articles (articles that met the inclusion criteria) were checked to ensure that all relevant articles were identified.

| Study quality and risk of bias assessment
The Cochrane Collaboration tool for assessing risk of bias was used to ascertain the quality of the eligible RCTs. Cochrane Collaboration tool assesses RCT validity based on five domains (selection, performance, attrition, reporting, and other). The Template for Intervention Description and Replication for population health and policy interventions (TIDieR-PHP) checklist 14 was used to evaluate the quality of the description of the interventions in the publications included in the review.

| Data extraction
A data extraction form was developed and piloted for the first five articles and then adjusted accordingly. Data were extracted by one author (Hadeel Zaghloul) and verified by another (Abdullah Elzafarany). Discrepancies were resolved by consensus or by consultation of a third party (Shahrad Taheri). We extracted study identification details, study design and methods, population characteristics, inclusion and exclusion criteria, interventions and outcomes.

| Analysis
No statistical analysis or meta-analyses were possible due to the extent, diversity and quality of data available. Data from the eligible trials was extracted and reported in a systematic manner.

| Study selection
The electronic database search identified 8612 potentially relevant articles for screening. No additional results were identified through manual searches. Following title and abstract screening, 290 articles remained. After examining the full text in more detail, 29 RCTs were deemed eligible for inclusion in the review. Interventions that used dietary intervention in combination with physical activity (three studies) or behavioural modification (four studies) were also included. Figure 1 shows the study selection process. Table 2 provides the details of the 29 included studies. A total of 2792 adults were recruited in the 29 RCTs. All but one trial 15 recruited people with overweight and obesity. Sixteen trials (55%) included women only and four (14%) included only post-menopausal women. Seven trials (24%) recruited individuals with the metabolic syndrome, seven (24%) with T2DM, 2 (7%) reported that subjects had diabetes but did not specify which type, and one trial (3%) recruited individuals with psoriasis. Ten trials (35%) recruited individuals with no reported obesity complications or comorbidities. One trial (3%) did not report on the presence or absence of obesity complications. 16 Twenty-three trials (79%) were conducted in Iran, three (10%) in Israel, one (3%) in Saudi Arabia, one (3%) in Kuwait and one (3%) in the United Arab Emirates. Only one study (3%) 17 recruited participants with a mean BMI ≥35 kg/m 2 in only one arm (the mean BMI in the other arm was <35 kg/m 2 ). Fourteen trials (48%) recruited participants with mean BMI ≥30 kg/m 2 . Two trials (7%) did not report on BMI.

| Study characteristics
Seventeen trials (59%) recruited middle-aged individuals and only four trials (14%) recruited individuals with a mean age < 35 years. Two trials (7%) did not report the mean age of individuals. One trial (3%) followed up the intervention for 2 years, 18 two trials (7%) for 1 year, 19,20 one trial (3%) for 8 months, four trials (14%) for 6 months and the majority of trials followed up on the intervention for less than 6 months. The shortest follow up duration was 20 days. 21 Fourteen (48%) of the trials used a control group that received no intervention and 18 studies (62%) compared between different interventions. Twelve trials (41%) used energy restricted diets, six (21%) used fat restriction, and three trials (10%) used low carbohydrate (CHO) diets in at least one arm of their interventions. Three trials (10%) described the use of Dietary Approaches to Stop Hypertension (DASH) diet, two trials (7%) described using a Mediterranean diet and one trial (3.%) described using AHA (American Heart Association) diet. Two trials (7%) investigated the effect of supplementing diets with nuts, one using cashews (10% of caloric intake) and the other using pistachios (two snacks of 25 g). Three trials (10%) described the use of dairy products, two (7%) used soymilk, one (3%) used tomato juice and one (3%) used diet beverages and water. Only three trials (10%) reported on providing exercise as a component of the intervention in at least one arm.

| Outcomes
A detailed description of the weight loss outcomes of the interventions is provided in Table 3 AHA (American Heart Association) diet: The AHA recommends a diet that will reduce risk of CVD. It recommends that individuals consume a variety of fruits, vegetables, and grain products, especially whole grains; choose fat-free and low-fat dairy products, legumes, poultry, and lean meats; and eat fish, preferably oily fish, at least twice a week.
c DASH (Dietary Approaches to Stop Hypertension) diet: DASH diet is especially recommended for people with hypertension or prehypertension to help control blood pressure. In addition to being a low sodium plan, the DASH diet is based on eating foods rich in fruits and vegetables, and low-fat or non-fat dairy, with whole grains. It is a high fibre, low to moderate fat diet, rich in potassium, calcium, and magnesium. d Mediterranean diet: A Mediterranean diet is based on traditional healthy eating habits of people from countries bordering the Mediterranean Sea. It is high in vegetables, fruits, legumes, nuts, beans, cereals, grains, fish, and unsaturated fats such as olive oil.
Usually, it also has a low intake of meat and dairy foods.  (Table 2) were randomly assigned to one of three diets: low-fat (energy intake limited to energy intake of 1500 kcal per day for women and 1800 kcal per day for men); Mediterranean, energy restricted; or low-CHO, energy unrestricted. 27 The rate of adherence to the study diet was reported to be 95.

| Study quality and risk of bias assessment
There was a paucity of full descriptions for the weight loss interventions. Figure 2 (15) 87 (12) .    While several studies reported on weight loss and glycaemic status, none of the trials reported on diabetes remission as an outcome.
T2DM remission is increasingly a realistic goal with evidence supporting that weight loss is an effective management for the prevention, 35  Combining exercise with dietary interventions has a positive impact on weight loss and its maintenance and also on obesity complications. 39 A recent review examined physical activity interventions in Arabic speaking countries and found that the majority of the interventions (97%) resulted in an improvement of measured health outcomes (P < .05). 40 Only four (13.7%) of the reviewed trials in our review inte- Over the past few decades, the MENA region has witnessed major economic, social, lifestyle, and political changes that have potentially contributed to the rise in obesity prevalence. There are many genetic, geographical, cultural, and lifestyle patterns that set the MENA region apart from the rest of the world and that could affect the success of weight loss interventions. However, none of the included studies assessed quantitatively or qualitatively the factors that are associated with successful weight loss in this population. This could be a consideration for future studies in order to improve weight loss services in this region.
Our review was comprehensive in including studies irrespective of date of publication or language. The studies identified also included those with obesity complications and comorbidities. The studies, however, were too diverse to include in a meta-analysis. Clinical research is developing in the MENA region and there is a greater acceptance of clinical research participation amongst the MENA population. 43 It is envisaged that greater quality studies will emerge and increasing cooperation amongst MENA countries will result in a stronger evidence base for obesity to be tackled in the region.

| CONCLUSION
Despite the rise in obesity prevalence in the MENA region, the RCTs examined in this review reported a wide range of weight loss responses to the interventions employed. Most interventions were F I G U R E 4 Quality assessment of individual studies adopted from interventions conducted in the western world, which may not be suitable for the MENA region. The short-term duration of interventions is also problematic as obesity is chronic disease. Several deficiencies were noted in the reporting the methodological aspects of the studies and future studies should include full descriptions of the interventions, study design, and study conduct. Our review identified that culture sensitive studies with longer duration of follow-up and evidence-based designs are needed to adopt and deliver effective interventions for the treatment of obesity in the MENA region.