Fitness & nutrition news: week 38 of 2026

Week 38 of 2026 is packed with applied science: from Japanese colored rice with surprising metabolic properties to the link between ultra-processed foods and hidden fat in muscle. We also see publication of the optimal whole-grain intake for heart health, a pioneering study on reversing biological age through diet, and a massive review on treatments for knee osteoarthritis. The roundup is completed by a curious finding about smell during training and a damning analysis of prolonged sitting. Here are the 7 most relevant stories.

Black and green Japanese rice may improve your metabolic health

Researchers have discovered that Japanese black and green rice varieties contain unusual and potentially beneficial fats, and that they digest more slowly than common white rice. This combination of properties makes these colored rice varieties promising candidates for foods designed specifically to improve blood glucose control and metabolic health.

Source: ScienceDaily — Nutrition

Ultra-processed foods accumulate fat inside thigh muscle

An MRI study of 615 adults at risk for knee osteoarthritis has revealed that those who consume more ultra-processed foods show greater fat accumulation inside their thigh muscles. The striking part: the association held even after adjusting for total calories, physical activity, and other factors, suggesting it's not just about eating more, but what you eat. This intramuscular fat can weaken knee support and accelerate osteoarthritis.

Source: ScienceDaily — Fitness

Between four and six daily servings of whole grains protect the heart

A review of 87 clinical trials has identified the sweet spot for whole-grain intake for cardiovascular health: between four and six servings per day. Researchers observed improvements in body weight, waist circumference, blood pressure, cholesterol, blood glucose, triglycerides, and several inflammation markers. Whole-grain bread, oats, brown rice, and other unrefined cereals can do far more for your heart than it seems.

Source: ScienceDaily — Nutrition

A low-fat diet reverses biological age markers in just four weeks

Older adults who modified the balance of fats, carbohydrates, and animal protein in their diet showed signs of reduced biological age after just four weeks. The strongest effect was observed in participants who followed a low-fat omnivorous diet with a higher proportion of carbohydrates. Though a small, preliminary study, it opens the door to rapid dietary interventions with measurable impact on aging biomarkers.

Source: ScienceDaily — Nutrition

Smelling chocolate during training helps you complete more reps without feeling more tired

In a curious experiment, simply smelling chocolate helped several men complete more leg extension reps without perceived exertion increasing. The effect was more pronounced with dark chocolate. Researchers believe that familiar food aromas may activate brain reward circuits and anticipation of eating, influencing motivation and physical performance in ways we're only beginning to understand.

Source: ScienceDaily — Nutrition

Knee braces, exercise, and aquatic therapy: what works best against knee osteoarthritis

A meta-analysis of 139 clinical trials with nearly 10,000 patients has identified the most effective treatments for knee osteoarthritis. Knee braces ranked first overall in reducing pain, stiffness, and mobility problems. Aquatic therapy stood out especially for pain, and regular exercise consistently improved both pain and physical function. In contrast, more high-tech therapies like ultrasound produced disappointing results.

Source: ScienceDaily — Sports Medicine

Each extra hour of uninterrupted sitting increases cancer death risk by 9%

It's not just how much time you spend sitting, but how you do it. A study found that each additional hour of prolonged sitting (without getting up) was associated with a 9% higher risk of cancer death, even after adjusting for total physical activity. In contrast, interrupting those periods with movement showed the opposite pattern: replacing one hour of continuous sitting with light activity was linked to a 12% lower risk. Standing up every hour can make the difference.

Source: ScienceDaily — Sports Medicine