Preventing Metabolic Syndrome with Diet: What the Research Tells Us
Metabolic Syndrome (MetS) is a constellation of risk factors associated with heart disease, stroke, diabetes, and other adverse health conditions. An individual with three (or more) of the following is considered to have MetS: obesity/overweight as measured by waist circumference, high triglycerides, low HDL (good cholesterol), high fasting blood sugar, and high blood pressure. Compared to metabolically healthy individuals, persons with MetS are five times more likely to develop type 2 diabetes, three times more likely to develop stroke, and two times more likely to develop heart disease.
MetS is characterized by metabolic dysfunction – abnormal or impaired metabolic processes that lead to too much or too little of essential components needed to maintain health – and MetS becomes much more common with aging. In the United States, only around 12.5 percent of adults are considered metabolically healthy, meaning they are free of all MetS components. Those most likely to be metabolically healthy include younger individuals, women, non-smokers, and physically active individuals. Socioeconomic factors, such as education and income, also play a role in both the presence of and remission from MetS.1
Both nutritional excesses and nutritional deficiencies are linked to the development of MetS. It makes sense then, that an appropriate diet can be an effective strategy for preventing and even reversing MetS. Because so much information is available in pop culture about diets and health, it can be difficult to know which advice is the best. The following gives a look into the research regarding some of the most well-studied diets and how these diets can help prevent or reverse MetS.
Diet Types and MetS
1. Mediterranean Diet
Generally considered to be the most well-researched diet for addressing a host of chronic health conditions, a Mediterranean-style diet is a great place to start for most individuals. Rich in plants and low in processed foods, a Mediterranean-style diet places an emphasis on fresh, whole foods like vegetables and fruits, whole grains, olive oil, and other omega-3 fatty acid-rich foods (fish and nuts). The high intake of leafy green vegetables, fresh fruits, and the use of spices makes it a polyphenol and carotenoid (antioxidants) rich diet as well.
Eating a Mediterranean-style diet is associated with improvements in multiple MetS components, including reduced blood pressure and better cholesterol levels. It is also associated with a decreased risk of type 2 diabetes and cardiovascular disease, and it has an inverse association with mortality. In other words, closely following a Mediterranean-style diet is linked to a longer, healthier lifespan. A Mediterranean-style diet helps prevent excess visceral fat (fat that surrounds organs and causes metabolic dysregulation) and inflammation.2,3
A typical macronutrient breakdown for a Mediterranean-style diet includes 35-45 percent of daily calories from fats, mostly in the form of monounsaturated fatty acids, with extra virgin olive oil and nuts as the primary sources – along with omega-3 fatty acids from fish. Carbohydrates, mostly from vegetables, fruits, and whole grains, make up 35-45 percent of daily calories. Protein comprises 15-18 percent of daily calories, mainly from beans, legumes, and lean animal protein sources like fish, seafood, and lean meats.2
In the 1990s, the DASH diet became a popular approach for managing high blood pressure. A low-fat nutritional plan, the DASH diet is rich in fiber from vegetables, fruit, and whole grains. It is comprised of approximately 27 percent of daily calories from fat, 55 percent from carbohydrates, and 18 percent from protein. The main difference between the DASH and Mediterranean-style diet is the DASH diet limits sodium to less than 2,300 mg daily.
Studies link the DASH diet to reduced blood pressure, improvements in cardiometabolic measures, decreased BMI and waist circumference, and a lower incidence of type 2 diabetes. Similar to the Mediterranean-stylet diet, closely following the DASH diet is associated with a lower risk of mortality, specifically from cardiovascular disease and cancer.2,4 The DASH diet is also linked to improved cellular immune function by promoting a healthier balance of white blood cell subpopulations.4
People often think of vegetarian or vegan diets when they hear the term “plant-based.” However, plant-based diets can encompass a wide variety of dietary patterns; for example, both the Mediterranean-style and DASH diets are primarily plant-based and could even be considered vegetarian or vegan diets based on the level of consumption of animal products. In general, plant-based diets reduce or restrict consumption of animal-derived foods, have a high intake of plant-sourced foods, are high in fiber, and contain a fatty acid profile rich in unsaturated fats.2
Whether completely free of animal-derived foods (vegan) or containing reduced animal foods (lacto-, ovo-, or pesco- vegetarian), plant-based diets are consistently associated with reduced cardiometabolic risk, including decreased body weight and risk of obesity. Vegetarian and vegan diets are also linked to reduced blood pressure, lower risk of cardiovascular disease, reduced incidence of type 2 diabetes, and lower all-cause mortality.2
One important consideration with plant-based diets is that the nutritional quality of the plant foods does make a difference. When switching to a vegetarian or vegan diet, it can be all too easy to replace the missing animal foods with packaged substitutes or simple carbohydrates. After all, white rice, potatoes, and pastas are generally plant based. Many packaged, processed foods are “accidentally vegan” – as well as high in carbohydrates and saturated fats, while low in fiber and micronutrients. When making the change to a plant-based diet, it helps to work with a dietitian to ensure a healthy balance of carbohydrates, protein, and fat to fit your lifestyle and metabolic needs.
4. Low-Carbohydrate Diets
Recently, low-carbohydrate and very low-carbohydrate (keto) diets have become popular, particularly within the health and wellness community on social media, and for good reason. Low-carbohydrate diets are associated with both weight loss and weight loss maintenance, something that can be particularly difficult with fad diets. Decreased blood pressure, improvements in cholesterol and triglycerides, increased HDL (good) cholesterol, reduced blood sugar, and improvements in insulin resistance are all well-studied metabolic effects of low-carbohydrate diets.2,5
Low-carbohydrate diets typically include less than 50 percent of daily calories from carbohydrates and are high in protein (20-30 percent of daily calories) and fat (30-70 percent of daily calories). Keto diets are typically comprised of less than 10 percent of daily calories from carbohydrates and are the highest in fat intake of all low-carb diets.2
Switching to a low-carbohydrate diet can have pitfalls, even more so when switching to a keto diet without proper guidance. Because keto diets are high in protein and fats, they have a tendency to be woefully deficient in fiber and antioxidants, unless the diet is well-planned to include them. A common misconception is that a keto diet can include all the bacon and cheese you want, but the research linking ketogenic diets to metabolic and other health improvements utilizes a well-formulated approach that includes sufficient leafy greens, low-sugar fruits and vegetables, and nuts and seeds. Recommended meats include fish and fresh, natural meats like beef, pork, and poultry rather than cured or processed meat products.
5. Intermittent Fasting
Intermittent fasting, another approach to improving MetS, is less diet focused and more behavior focused. Intermittent fasting alone doesn’t require eating any particular types of foods, but instead encourages eating only during limited time periods. Although there are a variety of studied intermittent fasting patterns, one of the most common is 16:8 time-restricted eating. With 16:8 eating, all food and drink (other than water and black coffee or tea) is consumed during an 8-hour period with the remaining 16 hours of each day reserved for fasting.
Intermittent fasting is linked to weight loss, decreased risk of cardiovascular disease and type 2 diabetes, and improvements in blood lipids and insulin resistance.2,6 Although intermittent fasting tends to have metabolic benefits regardless of diet, the best results are achieved when combining intermittent fasting with one of the healthy diets described above.
6. Gut Microbiome, Diet, and MetS
Another factor that can play a role in metabolic health is the gut microbiome. Both animal and human studies show a strong association between the gut microbiome and development of MetS. Gut microbes aid in digestion, absorption, and production of vital nutrients. They influence immune function, protect against disease, influence inflammation in the body, and play a role in drug metabolism.7
As you might have guessed, the types of foods you eat help determine which microbes make their home in your gut. Prebiotics are substances that act as food for probiotics, most often different types of fiber. Antioxidant compounds called polyphenols (found in plant foods) also support a healthy gut microbiome. Probiotic-rich, fermented foods like yogurt, sauerkraut, and kimchi also support a metabolic-friendly gut microbiome and promote weight management.
Where to start?
With so many well-studied diets to choose from, determining how to get started with dietary changes can be overwhelming. If you’re interested in a Mediterranean-style diet, consider taking a look at Thorne’s Metabolic Syndrome Guide. Complete with food lists, a sample eating plan, recipes, and lifestyle tips for incorporating exercise, stress management, and nutritional supplements, the MetS guide gives you the tools to be successful in managing your health – a whole-health, preventative approach with benefits that could last a lifetime.
- Hoveling LA, Liefbroer AC, Bültmann U, Smidt N. Understanding socioeconomic differences in metabolic syndrome remission among adults: what is the mediating role of health behaviors? Int J Behav Nutr Phys Act 2021;18(1):147. doi:10.1186/s12966-021-01217-5
- Castro-Barquero S, Ruiz-León AM, Sierra-Pérez M, et al. Dietary strategies for metabolic syndrome: a comprehensive review. Nutrients 2020;12(10):2983. doi:10.3390/nu12102983
- Di Daniele N, Noce A, Vidiri MF, et al. Impact of Mediterranean diet on metabolic syndrome, cancer and longevity. Oncotarget 2017;8(5):8947-8979. doi:10.18632/oncotarget.13553
- Rodríguez-López CP, González-Torres MC, Aguilar-Salinas CA, et al. DASH diet as a proposal for improvement in cellular immunity and its association with metabolic parameters in persons with overweight and obesity. Nutrients 2021;13(10):3540. doi:10.3390/nu13103540
- Gershuni VM, Yan SL, Medici V. Nutritional ketosis for weight management and reversal of metabolic syndrome. Curr Nutr Rep 2018;7(3):97-106. doi:10.1007/s13668-018-0235-0
- Kunduraci YE, Ozbek H. Does the energy restriction intermittent fasting diet alleviate metabolic syndrome biomarkers? A randomized controlled trial. Nutrients 2020;12(10):3213. doi:10.3390/nu12103213
- Festi D, Schiumerini R, Eusebi LH, et al. Gut microbiota and metabolic syndrome. WJG 2014;20(43):16079. doi:10.3748/wjg.v20.i43.16079