Beef, flank, steak, separable lean and fat, trimmed to 0" fat, choice, cooked, braised

Beef flank steak is a long, flat cut from the abdominal muscles of cattle, classified among leaner steak cuts due to its relatively low intramuscular fat content compared with more marbled cuts like ribeye or T‑bone. It has a rich culinary tradition across many cultures; historically, flank steak was favored in European and Latin American cuisines for its hearty flavor and fibrous texture. In Brazil and Argentina, this cut is often marinated and grilled over high heat to impart smokiness, while in North America it is a staple for dishes like fajitas and London broil. In Asian cuisine, especially Chinese and Vietnamese cooking, thinly sliced flank steak is prized in stir‑fries and noodle dishes because of its robust flavor and ability to hold up to quick, high‑heat cooking. (科学直通车) From a biological standpoint, flank steak originates from well‑used muscles, which contributes to its dense grain and pronounced texture. The muscle fibres run in parallel lines that are visible to the eye, which means that cutting across the grain (perpendicular to the fibres) is essential for tenderness in the finished dish. Unlike more tender cuts located near the spine, flank is lean and muscular, which makes it flavorful but potentially tough if not prepared properly. Due to this muscular structure, flank steak benefits significantly from marination — acids or enzymatic marinades help break down connective tissue and enhance tenderness. There are variations in how flank steak is labeled in markets around the world. For example, in Latin America, particularly Mexico, it may be labeled as "arrachera" and seasoned with regional spices, while in some European butchery traditions it is grouped with other flat cuts like skirt steak. Despite naming differences, the underlying cut remains muscle‑dense and nutrient‑rich. Also notable is its role in modern culinary trends: lean, high‑protein cuts like flank steak are increasingly popular among diners and home cooks seeking nutrient‑dense, lower‑fat proteins that still deliver robust flavor and versatility in recipes.

A 3‑ounce (85 g) cooked portion of beef flank steak delivers roughly 201 kcal, primarily from protein and fat, with negligible carbohydrates. In this portion, the steak provides ≈ 27 g of complete protein, supplying all nine essential amino acids crucial for muscle repair, immune function, and enzyme synthesis. Protein density in this cut surpasses that of many other common animal proteins when compared per calorie, making it valuable for strength training and metabolic health. The fat content (~16.44 g) in this lean cut provides energy and essential fatty acids; about 6.92 g are saturated fats, which should be moderated in populations at risk for cardiovascular disease, while the remainder includes monounsaturated and polyunsaturated fats important for cell membrane integrity and hormone production. Lipid profiles vary with factors such as cattle diet (grass‑fed vs grain‑fed), which can slightly shift the relative balance of omega‑3 and omega‑6 fatty acids. Beyond macronutrients, flank steak is a rich source of heme iron (3.33 mg) — the form more efficiently absorbed than plant‑based iron — which supports hemoglobin formation and oxygen transport. This is especially important for populations at risk for iron deficiency, such as menstruating women or endurance athletes. The cut also delivers ≈ 5.77 mg zinc, essential for DNA synthesis, immune competence, and cellular repair. Other notable micronutrients include potassium (~337 mg), which helps regulate blood pressure and muscle contractions, and selenium (~30.4 µg), an antioxidant that supports thyroid and immune function. Flank steak contains several B vitamins, including vitamin B12 (~3.3 µg), which is critical for neurological health and red blood cell formation, and niacin (~4.42 mg), vital for energy metabolism. Trace amounts of other B vitamins like riboflavin and thiamin further contribute to efficient cellular energy production. The absence of carbohydrates (0 g) and dietary fiber aligns flank steak with low‑carbohydrate and ketogenic dietary patterns. While sodium (70 mg) and cholesterol (72 mg) are moderate, they should be considered within the context of the total diet, especially in individuals monitoring cardiovascular risk factors.

Because flank steak is a form of unprocessed lean red meat, its consumption delivers several nutrients known to support physiological functions. High‑quality protein is associated with improved muscle maintenance and physical function, particularly in older adults. A systematic review found that protein and specific amino acids from beef had overall positive effects on markers of wellbeing and physical function in adults aged ≥50 years, including lean body mass maintenance. The heme iron provided by lean beef is critical for preventing iron‑deficiency anemia, a condition characterized by fatigue, weakness, and impaired cognition. Iron deficiency remains one of the most common nutrient deficiencies worldwide, particularly in women of reproductive age and in individuals with increased physiological demands, such as athletes or pregnant women. Flank steak’s iron is highly bioavailable, meaning the body absorbs it efficiently compared with non‑heme iron sources in plant foods. Zinc, another abundant mineral in flank steak, plays a pivotal role in immune competence, wound healing, and DNA replication. Adequate zinc intake supports leukocyte function, antibody production, and inflammatory regulation. Selenium’s antioxidant properties help protect cells from oxidative damage, support thyroid hormone metabolism, and contribute to immune resilience. B vitamins such as B12 and niacin are essential for neurological health, DNA synthesis, and metabolic energy production; B12 deficiency can lead to neuropathy and macrocytic anemia. From a metabolic perspective, the high protein content enhances satiety and can help regulate appetite and caloric intake, which is beneficial in weight management strategies. Lean protein intake also supports preservation of lean body mass during caloric restriction — a key factor in sustainable weight loss. While cardiovascular and cancer risk associations with red meat have been explored extensively, findings indicate that moderate intake of lean, unprocessed red meat may fit within balanced dietary patterns. Observational data link high overall red meat consumption with increased risk of certain chronic conditions, but lean cuts with limited saturated fat and careful portion control can mitigate these risks when part of a diversified diet including vegetables, whole grains, and legumes. (Harvard Health) Emerging research continues to refine our understanding of how lean red meat fits within health‑promoting diets, suggesting that quality, quantity, and overall dietary context matter more than single food avoidance. The nutrients in flank steak — protein, iron, zinc, B vitamins, and selenium — contribute to physiological functions that support muscle health, immune competence, and neurocognitive performance.

Despite its nutrient density, flank steak — like all red meats — contains saturated fat and cholesterol, which have historically been linked to elevated LDL cholesterol and cardiovascular disease risk when consumed in excess. Observational studies show associations between high red meat intake and increased risk of cardiovascular disease and type 2 diabetes; however, these associations are attenuated when lean, unprocessed cuts are emphasized and portion sizes are moderated. (Harvard Health) Population‑level recommendations often emphasize moderation: several health authorities advise limiting total red meat (especially processed forms) to around 12–18 ounces (≈350–500 g) cooked per week to balance benefits and risks. Excessive intake, particularly of processed meats with added salts and preservatives, is associated with higher colorectal cancer risk. The International Agency for Research on Cancer classifies unprocessed red meat as “probably carcinogenic to humans” based on epidemiological evidence. Individuals with pre‑existing cardiovascular conditions, high LDL cholesterol, or a family history of heart disease should discuss red meat intake with a healthcare provider. Similarly, people managing type 2 diabetes or metabolic syndrome may need to balance lean beef with plant‑based proteins to optimize glycemic control and cardiometabolic health. For those with gout or hyperuricemia, purine‑rich foods like beef may exacerbate symptoms; limiting intake and pairing with low‑purine foods can mitigate risk.

Selecting high‑quality flank steak begins at the butcher or grocery counter. Look for bright, cherry‑red color, firm texture, and minimal surface moisture; avoid meat that appears brownish or has a strong odor. Choosing cuts labeled “lean” or “choice” — which typically have lower fat content than “prime” grades — can reduce saturated fat intake. Trimming visible external fat further decreases overall fat content. For storage, raw beef flank steak can be refrigerated safely at 40°F (4°C) or below for 3–5 days; after cooking, store leftovers for 3–4 days in the refrigerator. If not using within this window, freezing at 0°F (–18°C) or below extends quality for 6–12 months. Thaw frozen steak in the refrigerator rather than at room temperature to minimize bacterial growth. Per USDA food safety guidelines, meat left at room temperature for more than 2 hours should be discarded to prevent foodborne illness. Cooking methods significantly influence both flavor and nutrient retention. Flank steak’s dense muscle fibers benefit from high heat, quick cooking methods such as grilling, broiling, or pan‑searing, which develop flavor without excessive moisture loss. Marinating steak for 2–24 hours with acidic components (such as citrus juice, vinegar, or yogurt) can help tenderize fibres while imparting flavor. After cooking, always rest steak for 5–10 minutes to allow juices to redistribute, ensuring a moist, tender result. If slow cooking or braising, low heat over longer periods breaks down connective tissue and enhances tenderness. Avoid deep frying or adding excessive saturated fats (like butter) during preparation. Instead, use minimal healthy oils (e.g., olive or avocado oil) when sautéing, and accompany flank steak with vegetables, whole grains, or legumes to round out the meal nutritionally.

Flank steak excels in recipes that highlight its rich umami flavor while minimizing toughness. Grilling or broiling to medium‑rare (internal temperature of 130–135°F / 54–57°C) preserves juiciness without overcooking. After resting, slice against the grain to shorten muscle fibres and maximize tenderness. Classic dishes include marinated flank steak served with chimichurri sauce and grilled vegetables, flank steak fajitas with peppers and onions, and Asian‑style stir‑fries with crisp vegetables and a light soy‑ginger sauce. Adding flank steak to salads or grain bowls provides balanced protein alongside fiber and phytonutrients. Slow‑cooked uses include braised flank steak in rich broths with root vegetables or shredded for tacos and sandwiches. Pairing flank steak with antioxidant‑rich side dishes such as roasted Brussels sprouts or sautéed spinach enhances nutrient diversity and supports cardiovascular health.

Certain combinations can enhance nutrient absorption from flank steak. Vitamin C‑rich foods (citrus fruits, bell peppers, tomatoes) consumed concurrently enhance non‑heme iron absorption from other foods in mixed meals. Although flank steak provides heme iron (already highly bioavailable), vitamin C can improve overall iron status when meals contain other iron sources. Zinc absorption may be modestly inhibited by phytates found in whole grains and legumes; balancing meals with cooked rather than raw grains and soaking legumes reduces this effect.

For ketogenic and low‑carbohydrate diets, flank steak is ideal due to its almost zero carbohydrate content and rich protein profile. Paleo and Whole30 diets — which emphasize unprocessed whole foods — also include flank steak when prepared without added sugars or processed ingredients. In balanced omnivorous diets like Mediterranean or DASH, flank steak can be incorporated in moderation (e.g., 1–2 times per week) alongside a variety of plant proteins, whole grains, fruits, and vegetables to support cardiovascular and metabolic health.

Source: USDA FoodData Central (FDC ID: 169434)