Effect of a Plant-Based vs Omnivorous Soul Food Diet on Weight and Lipid Levels Among African American Adults: A Randomized Clinical Trial

A Review of Plant-Based Diets for Obesity Management

OBJECTIVE

Obesity is the most prevalent chronic disease in the United States with over 70% of the American population suffering from overweight/obesity. Recently, the popularity of plant-based diets (PBDs) has grown, with individuals adopting these diets for ethical, health and environmental reasons. Our aim is to evaluate the effect of a PBD on weight loss among patients who are overweight or obese.

METHODS

A literature review of PBDs for the treatment of obesity was conducted using PubMed and Scopus. Our search yielded 27 intervention trials (3361 participants) and 6 metanalyses (9168 participants, 61 trials).

RESULTS

Among the intervention trials evaluated, 75% showed a significant increase in weight loss or decrease in weight in the intervention group, on average -5.0 kg (range -1.8 to -12.1 kg). Other outcomes included energy intake (-420 Kcal/d), systolic blood pressure (-3.78 mmHg), fasting plasma glucose (-2.0 mmol/L), hemoglobin A1c (-0.5%, -3.4 mmol/L), total cholesterol (-0.40 mmol/L), low-density lipoprotein (-0.38 mmol/L), triglyceride levels (+0.13 mmol/L), and fiber intake (+10.8 g/d). The 6 meta-analyses showed weight loss (average -2.9 kg, range -2.02 kg to -4.1 kg), body mass index reduction, and improvements in hemoglobin A1c, low-density lipoprotein, and total cholesterol.

CONCLUSION

PBDs result in significant weight loss and improve metabolic outcomes. PBDs offer a sustainable approach to long-term weight loss maintenance. Health care providers should encourage open discussions with their patients regarding their dietary habits to assist them in setting feasible lifestyle goals and consider shared medical appointments to support patients in transitioning to PBDs.

Differences in dietary acceptability, restraint, disinhibition, and hunger among African American participants randomized to either a vegan or omnivorous soul food diet

The Nutritious Eating with Soul study was a 24-month, randomized behavioral nutrition intervention among African American adults. This present study, which is a secondary analysis of the NEW Soul study, examined changes in dietary acceptability, restraint, disinhibition, and hunger. Participants (n = 159; 79% female, 74% with ≥ college degree, mean age 48.4 y) were randomized to either a soul food vegan (n = 77) or soul food omnivorous (n = 82) diet and participated in a two-year behavioral nutrition intervention. Questionnaires assessing dietary acceptability (Food Acceptability Questionnaire; FAQ) and dietary restraint, disinhibition, and hunger (Three-Factor Eating Questionnaire; TFEQ) were completed at baseline, 3, 6, 12, and 24 months. Mixed models were specified with main effects (group and time) and interaction effects (group by time) to estimate mean differences in FAQ and TFEQ scores using intent-to-treat analysis. After adjusting for employment, education, food security status, sex, and age, there were no differences in any of the FAQ items, total FAQ score, dietary restraint, disinhibition, and hunger at any timepoint except for one item of the FAQ at 12 months. Participants in the vegan group reported a greater increase in satisfaction after eating a meal than the omnivorous group (mean difference 0.80 ± 0.32, 95% CI 0.18, 1.42; P = 0.01). This is one of the first studies to examine differences in dietary acceptability, hunger, and other eating factors among African American adults randomized to either a vegan or omnivorous soul food diet. The findings highlight that plant-based eating styles are equally acceptable to omnivorous eating patterns and have similar changes in hunger, restraint, and disinhibition. These results suggest that plant-based eating styles can be an acceptable dietary pattern to recommend for cardiovascular disease prevention and may result in greater post-meal satisfaction.

Association between Plant-based Diet and Risk of Chronic Diseases and All-Cause Mortality in Centenarians in China: A Cohort Study

Background

Numerous studies have suggested the health benefits of a plant-based dietary pattern. However, whether this dietary pattern is associated with health benefits for centenarians remains unexplored. Our study aimed to investigate the correlation between 16 widely consumed Chinese food items and the incidence rates of chronic diseases and all-cause mortality among centenarians.

Methods

We conducted a dietary survey on 3372 centenarians with an average age of 102.33 y in China. After rigorous screening, we identified 2675 centenarians, who underwent a 10-y follow-up study with all-cause mortality as the primary outcome. We developed 6 dietary patterns on the basis of the food consumption frequency of each participant. To model the impact of missing values, we employed multiple imputation methods, verifying the robustness of models.

Results

The overall plant-based diet index (PDI), healthy plant-based diet index (hPDI), unhealthy plant-based diet index (uPDI), healthy plant-based foods index (HPF), unhealthy plant-based foods index (uHPF), and animal-based foods index (AF) scores among centenarians in China were 46.95 ± 6.29, 44.43 ± 5.76, 51.09 ± 6.26, 21.63 ± 4.79, 9.91 ± 2.41, and 14.59 ± 3.58, respectively. High scores of PDI, hPDI, and HPF were associated with a lower risk of chronic diseases. In the 10-y follow-up study, 92.90% of centenarians have died. The high scores of the PDI (HRPDI = 0.81), hPDI (HRhPDI = 0.79), and HPF (HRHPF = 0.81) scores were significantly associated with a lower risk of death compared with the low scores. Conversely, the high AF score (HRAF = 1.17) was significantly associated with a higher risk of death compared with the low scores.

Conclusion

Despite the fact that a higher score in both a predominantly plant-based dietary pattern and a healthy dietary pattern can decrease the death among centenarians, not all HPFs have this effect. A higher AF predicted a higher risk of mortality, whereas higher PDI, hPDI, and HPF were associated with a lower risk of mortality among Chinese centenarians.

Cardiometabolic Effects of Omnivorous vs Vegan Diets in Identical Twins: A Randomized Clinical Trial

Importance

Increasing evidence suggests that, compared with an omnivorous diet, a vegan diet confers potential cardiovascular benefits from improved diet quality (ie, higher consumption of vegetables, legumes, fruits, whole grains, nuts, and seeds).

Objective

To compare the effects of a healthy vegan vs healthy omnivorous diet on cardiometabolic measures during an 8-week intervention.

Design, Setting, and Participants

This single-center, population-based randomized clinical trial of 22 pairs of twins (N = 44) randomized participants to a vegan or omnivorous diet (1 twin per diet). Participant enrollment began March 28, 2022, and continued through May 5, 2022. The date of final follow-up data collection was July 20, 2022. This 8-week, open-label, parallel, dietary randomized clinical trial compared the health impact of a vegan diet vs an omnivorous diet in identical twins. Primary analysis included all available data.

Intervention

Twin pairs were randomized to follow a healthy vegan diet or a healthy omnivorous diet for 8 weeks. Diet-specific meals were provided via a meal delivery service from baseline through week 4, and from weeks 5 to 8 participants prepared their own diet-appropriate meals and snacks.

Main Outcomes and Measures

The primary outcome was difference in low-density lipoprotein cholesterol concentration from baseline to end point (week 8). Secondary outcome measures were changes in cardiometabolic factors (plasma lipids, glucose, and insulin levels and serum trimethylamine N-oxide level), plasma vitamin B12 level, and body weight. Exploratory measures were adherence to study diets, ease or difficulty in following the diets, participant energy levels, and sense of well-being.

Results

A total of 22 pairs (N = 44) of twins (34 [77.3%] female; mean [SD] age, 39.6 [12.7] years; mean [SD] body mass index, 25.9 [4.7]) were enrolled in the study. After 8 weeks, compared with twins randomized to an omnivorous diet, the twins randomized to the vegan diet experienced significant mean (SD) decreases in low-density lipoprotein cholesterol concentration (-13.9 [5.8] mg/dL; 95% CI, -25.3 to -2.4 mg/dL), fasting insulin level (-2.9 [1.3] μIU/mL; 95% CI, -5.3 to -0.4 μIU/mL), and body weight (-1.9 [0.7] kg; 95% CI, -3.3 to -0.6 kg).

Conclusions and Relevance

In this randomized clinical trial of the cardiometabolic effects of omnivorous vs vegan diets in identical twins, the healthy vegan diet led to improved cardiometabolic outcomes compared with a healthy omnivorous diet. Clinicians can consider this dietary approach as a healthy alternative for their patients.

Trial Registration

ClinicalTrials.gov Identifier: NCT05297825.

A Comprehensive Review of Phytonutrients as a Dietary Therapy for Obesity

Obesity is a complex medical condition mainly caused by eating habits, genetics, lifestyle, and medicine. The present study deals with traditional diets like the Mediterranean diet, Nordic diet, African Heritage diet, Asian diet, and DASH, as these are considered to be sustainable diets for curing obesity. However, the bioavailability of phytonutrients consumed in the diet may vary, depending on several factors such as digestion and absorption of phytonutrients, interaction with other substances, cooking processes, and individual differences. Hence, several phytochemicals, like polyphenols, alkaloids, saponins, terpenoids, etc., have been investigated to assess their efficiencies and safety in the prevention and treatment of obesity. These phytochemicals have anti-obesity effects, mediated via modulation of many pathways, such as decreased lipogenesis, lipid absorption, accelerated lipolysis, energy intake, expenditure, and preadipocyte differentiation and proliferation. Owing to these anti-obesity effects, new food formulations incorporating these phytonutrients were introduced that can be beneficial in reducing the prevalence of obesity and promoting public health.

Effect of Extraction Methods on the Antioxidant Potential and Cytotoxicity of the Combined Ethanolic Extracts of Daucus carota L., Beta vulgaris L., Phyllanthus emblica L. and Lycopersicon esculentum against Gastric Adenocarcinoma Cells

Frequent consumption of fruits and vegetables in the daily diet may alleviate the risk of developing chronic diseases. Daucus carota L. (carrot), Beta vulgaris L. (beetroot) Phyllanthus emblica L. (amla), and Lycopersicon esculentum M (tomatoes) are traditionally consumed functional foods that contain a high concentration of antioxidants, ascorbic acid, polyphenols, and numerous phytochemicals. This study assessed how three distinct preparation methods affect the phenolic, flavonoid, carotenoid, and ascorbic acid contents, antioxidant level, and cytotoxicity of the combined fruit extract. The fruit samples were taken in the ratio of carrot (6): beetroot (2): tomato (1.5): amla (0.5) and processed into a lyophilized slurry (LS) extract, lyophilized juice (LJ) extract, and hot-air oven-dried (HAO) extract samples. The sample extracts were assessed for their phytoconstituent concentrations and antioxidant and cytotoxic potential. The total phenolic content in LS, LJ, and HAO extracts was 171.20 ± 0.02, 120.73 ± 0.02, and 72.05 ± 0.01 mg gallic acid equivalent/100 g, respectively and the total flavonoid content was 23.635 ± 0.003, 20.754 ± 0.005, and 18.635 ± 0.005 mg quercetin equivalent/100 g, respectively. Similarly, total ascorbic acid content, carotenoids, and antioxidant potential were higher in the LS and LJ extracts than in HAO. Overall, the LS extract had a substantially higher concentration of phytochemicals and antioxidants, as well as higher cytotoxic potential, compared to the LJ and HAO extracts. The LS extract was tested in the MKN-45 human gastric cancer cell line to demonstrate its effective antioxidant potential and cytotoxicity. Hence, lyophilization (freezing) based techniques are more effective than heat-based techniques in preserving the phytoconstituents and their antioxidant and cytotoxic potential.

Vegetarian Diet for Cardiovascular Disease Risk Reduction: Cons

Numerous studies have reported that adopting a plant-based diet can significantly reduce the risk of cardiovascular diseases (CVDs). Not only does a vegetarian diet help mitigate the risk of these diseases, but it also contributes to enhancing environmental sustainability. However, it is not necessary to universally recommend a vegetarian diet as a preventive measure against CVDs. More research is needed to determine whether completely excluding animal products is necessary, or if adhering to a predominantly plant-based diet is sufficient. In this opinion paper, the potential adverse health effects of a vegetarian diet and the barriers associated with adopting it will be discussed, in order to provide a rationale for the disadvantages of using a vegetarian diet for CVD risk reduction.

Global Impacts of Western Diet and Its Effects on Metabolism and Health: A Narrative Review

The Western diet is a modern dietary pattern characterized by high intakes of pre-packaged foods, refined grains, red meat, processed meat, high-sugar drinks, candy, sweets, fried foods, conventionally raised animal products, high-fat dairy products, and high-fructose products. The present review aims to describe the effect of the Western pattern diet on the metabolism, inflammation, and antioxidant status; the impact on gut microbiota and mitochondrial fitness; the effect of on cardiovascular health, mental health, and cancer; and the sanitary cost of the Western diet. To achieve this goal, a consensus critical review was conducted using primary sources, such as scientific articles, and secondary sources, including bibliographic indexes, databases, and web pages. Scopus, Embase, Science Direct, Sports Discuss, ResearchGate, and the Web of Science were used to complete the assignment. MeSH-compliant keywords such "Western diet", "inflammation", "metabolic health", "metabolic fitness", "heart disease", "cancer", "oxidative stress", "mental health", and "metabolism" were used. The following exclusion criteria were applied: (i) studies with inappropriate or irrelevant topics, not germane to the review's primary focus; (ii) Ph.D. dissertations, proceedings of conferences, and unpublished studies. This information will allow for a better comprehension of this nutritional behavior and its effect on an individual's metabolism and health, as well as the impact on national sanitary systems. Finally, practical applications derived from this information are made.