Major Review Finds Intermittent Fasting No Better Than Traditional Dieting

Research published February 11, 2026, in JACC challenges the long-standing debate over whether low-carbohydrate or low-fat diets are superior for heart health. The Harvard-led study tracked nearly 200,000 U.S. adults for over three decades and found that both dietary patterns were associated with approximately 15% lower coronary heart disease risk when built around high-quality, nutrient-dense foods—but only when emphasizing plant-based proteins, whole grains, and healthy fats.

The study revealed a stark contrast: versions of these diets constructed from refined carbohydrates and animal-based fats and proteins were linked to higher heart disease risk and worse metabolic health markers. Lead researcher Zhiyuan Wu from Harvard T.H. Chan School of Public Health emphasized that conflicting results in past studies likely stemmed from not accounting for food quality, as people can follow low-carb or low-fat patterns in vastly different ways.

The findings suggest that Americans would benefit more from focusing on incorporating vegetables, legumes, whole grains, nuts, and olive oil rather than fixating on macronutrient percentages. This research adds important nuance to dietary guidance at a time when the 2025-2030 Dietary Guidelines for Americans have placed renewed emphasis on whole, minimally processed foods.

Stanford Medicine researchers reported in January 2026 that a short-term, calorie-restrictive diet significantly improved both symptoms and biological markers in patients with mild-to-moderate Crohn's disease. The national randomized controlled trial, published in Nature Medicine, found that approximately two-thirds of participants following a fasting-mimicking diet experienced symptom improvement—a notable finding in a field that has long lacked large-scale dietary intervention studies.

"What should I eat?" remains one of the most common yet difficult-to-answer questions from inflammatory bowel disease patients. This research offers a potential evidence-based answer for those with Crohn's disease, a chronic inflammatory condition affecting millions worldwide. The intervention involved a structured, temporary reduction in caloric intake rather than long-term dietary restrictions.

While the findings are promising, researchers acknowledge the inherent challenges in studying dietary interventions, including the difficulty of blinding participants and the strong placebo effect associated with diet changes. The study represents an important step toward developing practical, scientifically-backed dietary guidance for IBD patients who have historically received limited concrete advice about nutrition's role in managing their condition.