Visceral fat is the fat under the muscles of the abdomen which surrounds the internal organs. It is well known as the “unhealthy” fat, as it has the highest correlation to disease compared to excess fat in other areas of the body.
It is also known to be the “hardest” to burn off through lifestyle habits, but there have been a number of good studies on this, so here are four I found particularly interesting:
- https://www.nature.com/articles/s41598-017-13722-4
- https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-022-02525-8
- https://www.nature.com/articles/s41467-022-35704-5
- https://pmc.ncbi.nlm.nih.gov/articles/PMC6770155/pdf/nutrients-11-02216.pdf
The details:
A study called the Dietary Intervention Randomized Controlled Trial PoLyphenols UnproceSsed (DIRECT-PLUS) explored the effect of a “green-MED diet,” which is rich in polyphenols, on visceral adipose tissue (VAT).
The study lasted 18 months and involved 294 participants. It compared a green-MED diet to a traditional Mediterranean diet (MED) and a diet based on healthy dietary guidelines (HDG).
The researchers found that those following the green-MED diet experienced a greater reduction in VAT compared to the other two diets, even though the amount of weight loss was similar between the MED and green-MED diets.
The green-MED group’s VAT loss was more than double that of the HDG group.
Specific dietary components associated with greater VAT loss included:
- Increased consumption of green tea, walnuts, Wolffia globosa (duckweed), and dietary fiber.
- Reduced red meat intake. This was the only point I had issue with, as red meat is vastly different between traditionally farmed cattle and organic grass-fed cattle. The former is like eating poison and the latter is a superfood. They didn’t specify the source of red meat, so I’m assuming it’s the former and not the latter, which would drastically bias away from red meat.
The Importance of Polyphenols
The study authors suggest that the beneficial effects of the green-MED diet may be attributable to its high polyphenol content.
Polyphenols are plant compounds that have antioxidant and anti-inflammatory properties.
Specific polyphenols associated with greater VAT loss in the DIRECT-PLUS study included:
- Hippuric acid, a metabolite of various polyphenols.
- Urolithin A, a gut microbiota metabolite of ellagitannins found in walnuts and Wolffia globosa.
Study Limitations
The study authors acknowledge some limitations of the DIRECT-PLUS study:
Physical activity was self-reported, not objectively measured.
The study could not precisely estimate polyphenol intake beyond what was provided to the green-MED group.
Urine polyphenol analysis was based on spot samples, not 24-hour collections.
Additional Insights from Other Sources:
Supporting the focus on polyphenols, they found a strong association between hippurate, a metabolite of polyphenols, and increased gut microbiome diversity, as well as reduced odds of metabolic syndrome.
This source also found that higher intakes of fruit and whole grains were associated with higher hippurate levels both cross-sectionally and longitudinally.
This further strengthens the idea that a diet rich in polyphenols from sources like fruits, whole grains, and certain plant-based foods like those included in the green-MED diet may contribute to a reduction in visceral fat and overall metabolic health.
BMI-Adjusted Fat Depots:
Individuals with the same BMI can have significantly different fat distributions, and these variations can impact cardiometabolic risk.
This study used deep learning models to analyze MRI data from over 40,000 individuals in the UK Biobank to measure visceral, abdominal subcutaneous, and gluteofemoral fat depot volumes, independent of BMI.
Their key findings included:
- VAT adjusted for BMI (VATadjBMI) was associated with a higher risk of type 2 diabetes and coronary artery disease.
- GFAT adjusted for BMI (GFATadjBMI) was associated with a lower risk of these conditions.
- An “ideal diet,” characterized by higher fruit, vegetable, and fish intake and lower processed meat and sugary drink intake, was linked to reduced VATadjBMI.
Implications for Obesity Interventions
Both sources suggest that focusing solely on weight loss or BMI reduction may not be sufficient to address cardiometabolic risks associated with fat distribution.
Future obesity interventions and clinical trials should consider including measures of local adiposity, like VATadjBMI, as endpoints to better capture the metabolic health benefits associated with body composition changes.
Conclusion
The sources highlight the importance of targeting visceral fat reduction for improved metabolic health and suggest that dietary strategies rich in polyphenols, like the green-MED diet, can be effective in achieving this goal.
Foods rich in polyphenols (be sure to eat organic whenever possible):
-
Fruits:
- Berries (blueberries, blackberries, strawberries, raspberries)
- Pomegranates
- Cherries
- Plums
- Apples
- Red and purple grapes
- Oranges and citrus fruits
Vegetables:
- Artichokes
- Red onions
- Spinach
- Broccoli
- Red cabbage
- Potatoes (with skin)
Beverages:
- Green tea
- Black tea
- Red wine
- Coffee
- Cocoa and dark chocolate
Herbs and Spices:
- Cloves
- Dried oregano
- Thyme
- Rosemary
- Peppermint
- Cinnamon
Nuts and Seeds:
- Almonds
- Chestnuts
- Flaxseeds
- Hazelnuts
Legumes:
- Black beans
- Soybeans
- Tofu
Additional Dietary Recommendations:
Reduce TRADITIONAL Red Meat Intake: The DIRECT-PLUS study specifically found that reducing red meat consumption (from traditional farms) was associated with greater VAT loss. Grass-fed red meat, in my opinion, could help with visceral fat loss, due to the high amount of CLA and Omega 3 fats. Wild cold-water fatty fish would have a similar effect.
Increase Dietary Fiber: A high-fiber diet can help promote a healthy gut microbiome, which is linked to better metabolic health.
Eat fermented foods: Kefir, sauerkraut, kimchi, unsweetened Greek yogurt, etc. all have positive effects on gut microbiome.
