Contrary to decades of dietary advice, data shows no significant difference between whole-fat and low-fat dairy. In fact, whole-fat dairy products are associated with decreased risks of diabetes and cardiovascular issues.

A study found that participants on a weight loss diet who used MCT oil lost more weight than those using olive oil. MCTs are processed differently, traveling directly to the liver to be burned for energy, which increases the thermic effect of food.

Instead of adhering to a strict diet label like vegan or pescatarian, Dr. Bolsiewicz advises focusing on nutrient quality. A gut-healthy, anti-inflammatory diet is achieved by consistently consuming these four "workhorses," which support the microbiome and calm the immune system, regardless of the diet's name.

In an industry-funded study, participants who replaced their typical low-fat or high-saturated-fat snacks with corn chips (like Doritos) showed improved cardiometabolic risk factors, including a better lipid profile, attributed to the corn oil's polyunsaturated fat content.

In a head-to-head study, a diet high in fermented foods like yogurt and kimchi significantly increased microbiome diversity and lowered markers of inflammation. A high-fiber diet did not consistently produce these effects, suggesting that introducing live microbes is a more direct strategy for improving gut health and immune status in Western populations.

While you cannot spot-reduce subcutaneous belly fat, you can influence the loss of dangerous visceral fat around organs. Diets lower in saturated fats, specifically from fatty land animal meats, are more conducive to reducing this specific type of abdominal fat.

Beyond lacking nutrients, processed foods contain additives like emulsifiers that are actively harmful. These chemicals, added for shelf stability, are known to disrupt the gut's critical mucus layer. This erosion of the natural barrier between your gut microbes and your body can directly lead to inflammation and contribute to metabolic syndrome.

The fitness trend of consuming very high amounts of protein (e.g., 1g per pound of body weight) is not supported by data. Amounts exceeding 1 gram per kilogram, especially from animal sources, can lead to systemic inflammation and promote the development of atherosclerosis (clogged arteries).

Not all fish oil is beneficial; polyunsaturated fats are prone to oxidation, which can be harmful. Consumers should consult third-party testers like IFOS and specifically look for a TOTOX (total oxidation) value under 10 to ensure the product is potent and free from rancid, inflammatory fats.