Lasagna has 124 kcal per 100 g. Pasta, cheese, and sauce stack into a calorie-dense layered dish. A restaurant slice runs 250–400 g and 400–700 kcal. Portion errors for calorie-dense foods reach 50–200% (Almiron-Roig et al., Appetite 2013). Weigh your slice once.
How should I track Lasagna with meat & sauce, frozen entree?
Prepared foods like Lasagna with meat & sauce, frozen entree can be tricky to track because the actual serving you get often differs from the label. Restaurant and deli portions are typically 30–50% larger than the stated serving size. A meta-analysis of dietary reporting (Wehling & Lusher, Am J Clin Nutr 2021) found that people underreport calorie intake by 25–30% on average — and prepared meals are a major contributor. The safest approach: weigh your actual portion as served. Also note that homemade and store-bought versions of the same dish can differ significantly in calories due to cooking methods and ingredients used.