Marcus T., 44M, presents with persistent fatigue, difficulty concentrating, and weight gain of 22 lbs over 3 years despite 'eating healthy.' He exercises 3x/week but feels exhausted after workouts rather than energized. Diet history: low-fat diet, whole grain cereals, vegetable oils (sunflower, canola), lean protein, fruit. He avoids red meat and saturated fat. Vitals: BP 128/82, BMI 29.4. Standard labs: fasting glucose 96 mg/dL, HbA1c 5.4%, total cholesterol 188, LDL 112, HDL 41, TG 198.