The main health benefit of lettuce and other greens in salads is fiber. Salads are usually full of nutritious fiber – just not for you! Fiber is actually food for the microbiome, the trillions of bacteria that live in your gut. Fiber is also key to metabolic health. Bacteria in your gut convert fiber into short-chain fatty acids, which can regulate immune function and keep inflammation in check.
To increase the fiber in your leafy green salad, add a variety of vegetables, such as broccoli and green peppers, and add beans and lentils.
But the healthiest salads include many other beneficial ingredients, such as antioxidants. Antioxidants are chemicals that are important to your liver and detoxify almost all environmental toxins that enter the body. Your liver needs these antioxidants to perform this magic trick.
For antioxidants, try chopped colorful vegetables (the darker the better), chopped fresh fruit, herbs (fresh or dried), and spices. Then add protein, such as free-range eggs, grass-fed beef, fish, chicken, tofu, beans, or lentils.
Add oils and fermented foods to your salad
Now add in some whole food oils including avocado, olives, nuts and seeds. Nuts and seeds (such as chia seeds and walnuts) are rich in the anti-inflammatory alpha-linolenic acid (ALA), an omega-3 fatty acid that reduces the risk of heart disease.
For other sources of omega-3s, try small fish like anchovies (commonly found in Caesar salads). You can also add other wild fish (sardines, salmon, mackerel) or chicken (free-range, pasture-raised chicken has fewer antibiotics)..
Cheeses are a fantastic addition because they contain single-chain fatty acids that protect against diabetes and heart disease. We’ve all been taught to avoid fats because they have more calories, but milk fatty acids are unique in that they have a special phospholipid at the end that prevents inflammation. Just don’t use American cheese, which isn’t actually cheese. Instead, try varieties like feta, cotija, parmesan and mozzarella.
Bonus points go to kale, cabbage, and Brussels sprouts—cruciferous vegetables that can boost your body’s natural antioxidant production and stimulate the liver’s production of detoxifying enzymes. Another bonus: fresh tomatoes contain lycopene, an antioxidant that supports eye function and prevents cataracts.
Adding fermented foods like kimchi and sauerkraut can improve the gut, as can homemade dressings made with natural, sugar-free yogurt. And fermented foods already contain short-chain fatty acids.
Avoid store-bought salad dressings
okay Now let’s talk about salad dressings. To make a great homemade dressing, look for ingredients like extra virgin olive oil, avocado oil, tahini, vinegar, Dijon, herbs, spices, and low-sugar citrus juices (lemon, lime, grapefruit).
Oleic acid in olive oil activates the liver and forms a factor that accelerates metabolism. The acetic acid in vinegar inhibits the enzyme that breaks down starches in the mouth, thus reducing the amount of glucose that appears in your bloodstream. Some homemade dressings get added antioxidants from spices and herbs like ginger, garlic, turmeric, oregano, and thyme.
But the same cannot be said for most store-bought clothes. Store-bought versions are often made with canola and soybean oils, which are loaded with linoleic acid, an anti-inflammatory omega-6 fatty acid.
They can also be hidden in large amounts of fructose (a sugar molecule), cane sugar, high-fructose corn syrup, or honey—which harms mitochondria, the energy-producing factories that power each of your cells. When your mitochondria don’t work properly, blood glucose and insulin rise, and your liver has no choice but to turn fructose into fat—causing fatty liver and insulin resistance, and potentially increasing your risk of developing heart disease, cancer, and diabetes.
You might be surprised how common it is for sugar to leak into glass containers. For example, high fructose corn syrup is the second ingredient in Kraft’s Creamy French dressing, which adds five grams of sugar. And watch out for fat-free dressings — Ken’s Sundried Tomato Vinaigrette, for example, has 12 grams of added sugar.
Store-bought dressings can also contain ingredients that are harmful to your gut and the trillions of bacteria that live there. These bacteria send chemical signals to your brain to feed. If you don’t feed your bacteria, they actually start feeding on you – stripping the protective layer of mucin from your gut cells. Over time, this can lead to irritable bowel syndrome, inflammatory bowel disease, and altered intestinal permeability, which some people call “leaky gut.” It can also cause systemic inflammation.
Store-bought dressings often contain emulsifiers, e.g Carboxymethylcellulose, polysorbate-80, or carrageenan, interferes with the separation of fat and water and can dissolve that protective mucin layer in your intestines. These pesky added sugars can also cause an overgrowth of bad microbiome bacteria, potentially leading to discomfort, gas, bloating, diarrhea and inflammation in the gastrointestinal tract.
Croutons and crisps
But that doesn’t mean you should skip getting dressed. Studies have shown that fats — such as those in avocados — actually help your body absorb nutrients from some vegetables. The key is to choose the right ingredients and ideally make your own dressing at home.
It’s also a good idea to stay away from “crispy” items (such as fried onions and tortilla strips), which are often fried in high-temperature seed oils, which carry the risk of developing trans fats and acrylamide, a known carcinogen. I would also suggest caution with dried fruit; some varieties and brands coat them with sugar to make them sweeter and more palatable.
And finally, avoid processed breads. A Caesar salad isn’t a Caesar salad without croutons, but commercial croutons are usually loaded with preservatives, sodium and vegetable oils. Bake your own croutons or pair your salad with a slice of sourdough bread. But please, don’t eat the fried tortilla bowl.
Robert H. Lustig Emeritus Professor of Pediatrics at the University of California, San Francisco and “Metabolic: The Allure and Lies of Processed Food, Nutrition, and Modern Medicine.”