Struggling with weight? Eat more legumes, cut red meat and skip soda

Struggling with weight? Eat more legumes, cut red meat and skip soda

Do you want to overcome obesity? A global review presents the strongest evidence on what to eat – and what to avoid – to manage weight and improve health.

In a study recently published in the journalNutrientsResearchers in Italy and Norway have summarized evidence linking certain food groups to overweight and obesity risks.

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Did you know that over 2.8 million deaths worldwide each year are linked to obesity? As obesity rates increase, it is critical to understand how our daily food choices affect weight management and overall health.

Food groups such as whole grains, fruits, vegetables, nuts, legumes, meats and sugary drinks play a critical role in energy balance, either supporting weight control or contributing to weight gain. However, clear nutritional recommendations can be confusing due to conflicting research results.

Understanding the true impact of different food groups on obesity could guide healthier lifestyles and more effective public health policies. Therefore, further comprehensive research is required to provide clearer guidance.

About the study

The "whole grain benefit" held steady - every 30g/day reduced the risk of obesity by 7%, with no decline even at 90g/day, in contrast to the meaningful returns of nuts.

The researchers conducted a review of the umbrella and systematically summarized findings from previous systematic reviews and meta-analyses. Four major databases, Medline, Embase, Web of Science and Epistemonikos, were thoroughly searched for relevant studies published up to June 2024.

The selection criteria included systematic reviews and meta-analyses of longitudinal studies, such as: B. Cohort studies and randomized controlled trials examining the association between consumption of specific food groups and the incidence of overweight and obesity in adults aged 18 years or older.

Studies were excluded if they involved children, animals, cross-sectional designs, non-systematic reviews, or were limited to data from a single country without broader applicability. 13 eligible studies were selected from an initial pool of 2,925 articles, covering an average of 166,100 participants and 36,760 cases per food group, although these numbers varied by food group.

Each included study was independently assessed for methodological quality by multiple researchers using the standardized tool “A Measurement Tool for the Assessment of Systematic Reviews” (AMSTAR-2). Data extraction included recording the number of studies, participants, cases, outcomes, exposure details, heterogeneity and key findings that clearly distinguish between high and low comparisons and dose-response relationships.

The results were then synthesized into visual summaries, including forest plots and dose-response curves, highlighting the significance and direction of associations. Any disagreements regarding assessments or data extraction were resolved through team consensus to ensure the reliability and accuracy of reported results.

Study results

The review found no solid evidence linking dairy intake to obesity, and the results varied widely depending on the type of dairy products examined.

The review synthesized data from systematic reviews involving an average of 166,100 participants per food group. High consumption of whole grains, fruits, nuts and legumes consistently showed protective effects against obesity and overweight, likely due to their high fiber content, which increases feelings of fullness and reduces calorie intake.

In particular, high intake of whole grains resulted in a significantly reduced risk of obesity, with clear dose-response relationships showing continued risk reduction with increased consumption. Similarly, the nuts showed beneficial effects at moderate consumption levels (~10 grams/day), although this protective effect appeared to increase at higher intakes.

Conversely, high consumption of red meat and sugary drinks significantly increased the risk of obesity and reinforces the public health message to limit these foods. Red meat's association with obesity may be due to its high calorie and saturated fat content, potentially promoting fat storage and weight gain. Sugary drinks were consistently associated with higher rates of obesity, reinforcing the robustness of this association to low heterogeneity across studies.

Interestingly, vegetables may show a nuanced U-shaped dose-response relationship, although this trend was not statistically significant. Moderate vegetable intake (~250-400 grams/day) appears to be beneficial, but very high intakes do not clearly confer more benefit.

Dairy products showed no significant association with obesity risk, and results in different types of dairy products were inconsistent, highlighting the need for further research.

While sugary drinks and whole grains showed consistent patterns across studies, foods like nuts and vegetables had more mixed results depending on how much people ate and how the studies were conducted.

Refined grains showed a nonsignificant trend toward increased obesity risk, particularly at higher consumption levels. This is likely due to their rapid digestion and high glycemic index, which causes spikes in blood sugar and insulin levels and may promote fat storage.

Although processed meat showed a trend toward an increased risk of obesity, the results were not statistically significant, based on low-quality evidence and varied widely across studies.

No available studies provided evidence of the association with obesity risk with fish, eggs, white meat and added sugar, highlighting significant gaps in nutritional research.

Overall, the research demonstrated substantial heterogeneity across studies, particularly for nuts and processed meats, indicating variable results influenced by differences in study design, participant demographics, and diet assessment methods. However, the associations for sugary drinks and whole grains were more consistent with less heterogeneity.

These results support dietary guidelines that emphasize increased plant-based foods, limited sugary drinks, and red meat intake to combat obesity.

Conclusions

In summary, this review highlights clear dietary patterns that influence the risk of obesity. Diets rich in whole grains, nuts, legumes, and fruits appear to be beneficial in reducing obesity and align with current public health recommendations. Conversely, frequent consumption of red meat and sugary drinks significantly increases the risks of obesity.

Despite consistent results for key food groups, high variability between studies highlights the complexity of diet-accessory relationships that require careful interpretation. Future research should examine understandable food groups such as fish, eggs, white meat, and added sugars and explore dietary nuances and provide clearer, actionable guidance.

Ultimately, consuming balanced diets that emphasize whole foods and moderation in risk articles could significantly reduce the health risks associated with obesity and improve public health outcomes.

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