London broil is one of the leaner beef options you can buy, with roughly 140 calories and just 1.3 grams of saturated fat per serving when trimmed. As a high-protein, nutrient-dense cut, it fits comfortably into a balanced diet, especially when you choose it over fattier steaks and keep portions reasonable.
What London Broil Actually Is
London broil isn’t a specific cut of beef. It’s a label that started as a recipe name for marinated flank steak, but grocers now apply it to several lean, thick cuts from the round and sirloin sections of the cow. Most often, what you’ll find labeled “London broil” at the store is top round steak. These cuts share a common trait: they’re lean, relatively affordable, and tougher than premium steaks because the muscles do more work during the animal’s life. That toughness is also why they carry less intramuscular fat.
Nutrition Per Serving
A serving of top round (the most common London broil cut) clocks in at about 140 calories with 1.3 grams of saturated fat. It’s an excellent source of protein, delivering a dense amount per calorie without the fat load of more marbled cuts. For comparison, a similar portion of ribeye contains about 202 calories and 3.4 grams of saturated fat, more than 50% more saturated fat than London broil.
Where London broil really shines is its micronutrient profile. A single serving provides roughly 58% of your daily vitamin B12, a nutrient essential for nerve function and red blood cell production. It also covers about 34% of your daily selenium (which supports thyroid function and acts as an antioxidant), 29% of your daily zinc (important for immune health), and 11% of your daily iron. These nutrients are harder to get in adequate amounts from plant sources alone, making lean beef a particularly efficient way to meet those needs.
How It Compares to Fattier Cuts
If you’re choosing between London broil and a ribeye or T-bone, the calorie difference per serving is modest, but the saturated fat gap is significant. London broil has about 2.2 grams of saturated fat per 100 grams of cooked lean meat, while ribeye has 3.4 grams. That difference compounds over the course of a week if you eat beef regularly. The U.S. Dietary Guidelines recommend keeping saturated fat below 10% of daily calories, which is about 22 grams on a 2,000-calorie diet. Choosing leaner cuts like London broil gives you more room within that budget.
The practical tradeoff is tenderness and flavor. London broil requires a good marinade and careful cooking (sliced thin against the grain) to avoid being chewy. But nutritionally, it gives you nearly the same protein and micronutrients as premium cuts while keeping fat lower.
Red Meat in a Balanced Diet
The Dietary Guidelines for Americans recommend about 26 ounce-equivalents per week from the combined meats, poultry, and eggs group for a 2,000-calorie diet. The guidelines also consistently link diets higher in red and processed meats with worse health outcomes, while diets emphasizing lean meats, seafood, legumes, and vegetables are associated with better ones. The key distinction is between lean, unprocessed red meat (like London broil) and processed varieties like hot dogs, sausages, and deli meats.
Replacing some red meat servings with seafood, beans, or lentils can lower your saturated fat and sodium intake. But when you do eat red meat, choosing a lean cut like top round is one of the better options available. You’re getting the protein and micronutrient benefits of beef without the saturated fat penalty of heavily marbled steaks.
Cooking Method Matters
How you cook London broil affects its healthfulness beyond the raw nutrition numbers. Cooking any muscle meat at high temperatures, above about 300°F, produces compounds called heterocyclic amines. Grilling directly over an open flame adds another concern: fat dripping onto the heat source creates smoke that deposits polycyclic aromatic hydrocarbons onto the meat’s surface. Both types of compounds have been linked to cancer risk in lab studies, according to the National Cancer Institute.
You don’t need to avoid high-heat cooking entirely, but a few habits reduce your exposure significantly:
- Flip frequently. Turning the meat often on the grill reduces harmful compound formation compared to letting it sit undisturbed.
- Pre-cook briefly in the microwave. Even a few minutes of microwaving before grilling or broiling cuts down the time the meat spends at high heat, substantially lowering compound formation.
- Trim charred portions. The blackened edges carry the highest concentrations.
- Skip the drippings gravy. Fat drippings from high-heat cooking can concentrate these compounds.
London broil’s leanness actually works in its favor here. Less fat means less dripping onto the flame, which means less smoke and fewer surface deposits on the meat. Marinating before cooking (which most London broil recipes call for anyway) may also help create a barrier that reduces compound formation at the surface.
Who Benefits Most From London Broil
London broil is a particularly good fit if you’re watching your calorie or fat intake but still want the nutritional density of beef. It works well for people focused on high-protein eating, whether for muscle building, weight management, or simply staying full between meals. The high B12 and iron content also makes it a solid choice for anyone at risk of deficiency in those nutrients, including older adults and people with higher iron needs.
The bottom line: London broil is one of the healthier ways to eat beef. It’s lean, packed with protein and essential micronutrients, and lower in saturated fat than most popular steak cuts. Keeping portions moderate, choosing it over processed meats, and being mindful of cooking temperature are the main things to get right.