Natural Vasodilators for Workouts: The Whole Foods the Research Actually Supports

Honey and beets are both natural vasodilators, and neither one comes in a scoop. Before you reach for a tub of powder, it is worth knowing that most of the research behind "nitric oxide" pre-workouts started with whole foods, not supplements. Beet juice, leafy greens, watermelon, dark chocolate, and a handful of other foods have real trial data showing they widen blood vessels and improve blood flow during exercise. This article ranks those foods by the strength of the evidence, with the doses and timing the actual studies used. If you are also dialing in the rest of your plate, the macro calculator is a useful starting point for building a pre-workout meal around these foods rather than around a supplement stack.

How food-based nitrate turns into a vasodilator

Nitrate-rich vegetables work through a well-mapped pathway. Dietary nitrate is absorbed, concentrated in the salivary glands, and converted to nitrite by bacteria on the back of the tongue. Swallowed nitrite is then reduced to nitric oxide in the acidic environment of the stomach and in tissues under low-oxygen conditions, and nitric oxide is what relaxes vascular smooth muscle and widens blood vessels. This nitrate-nitrite-nitric oxide pathway is described in detail in a review published in the Annual Review of Nutrition. It matters for this article because it explains why the effect is not unique to one "superfood": any food with meaningful nitrate content can feed the same pathway, and antibacterial mouthwash or spitting out saliva can blunt it, since the oral bacteria step is not optional. Foods discussed later, like watermelon and citrus, work through separate mechanisms (citrulline and flavonoid-driven nitric oxide synthase activity), which is why they are grouped by mechanism as well as by evidence strength below.

Tier 1: beetroot, and why juice or cooked beets beat a single raw one

Beets have the deepest research base of any food vasodilator. A 2017 meta-analysis in Nutrients pooling multiple randomized trials found that dietary nitrate supplementation, primarily from beetroot juice, produced small but consistent improvements in time-to-exhaustion and submaximal exercise economy. The dose-response relationship was mapped by Wylie and colleagues (2013), who found that 140 mL of beetroot juice (about 8 mmol nitrate) reduced oxygen cost during moderate exercise and extended time-to-task failure by around 14 percent compared with placebo, while a larger 280 mL dose produced similar or slightly better effects; both were consumed roughly 2 to 3 hours before exercise, which is how long it takes plasma nitrite to peak. A review in Sports Science Exchange puts the effective range at roughly 5 to 9 mmol nitrate, which translates to about 300 to 500 mL of beetroot juice or, in whole-food terms, roughly 200 to 300 grams of cooked beets. One raw beet, at typical serving sizes, usually falls short of that: nitrate content varies with soil and growing conditions, but a single small beet rarely delivers more than 1 to 2 mmol. That is why the research almost always uses juice or a larger cooked portion rather than a single piece of raw root vegetable.

Tier 1: leafy greens, ounce for ounce the highest-nitrate food group

Leafy greens supply about 80 percent of dietary nitrate intake in most diets, according to the foundational food-nitrate survey by Hord, Tang, and Bryan (2009), published in the American Journal of Clinical Nutrition. Their analysis, along with later food-composition surveys, ranks arugula as one of the single highest-nitrate vegetables tested, with concentrations often exceeding 400 to 480 mg nitrate per 100 grams, meaningfully higher than beetroot on a weight basis. Spinach, chard, and beet greens are also very high, generally in the 100 to 700 mg per 100 g range depending on growing conditions, and are classified as "very high nitrate" foods in a 2024 review in Foods. Because arugula and spinach are more nitrate-dense than beets by weight, a moderate salad, roughly 75 to 100 grams of arugula or a large handful of raw spinach, can approach the same 300 to 500 mg nitrate range used in the positive beetroot trials, without juicing anything. The practical tradeoff is volume: greens are easy to eat in a salad but harder to concentrate into a small serving the way juice does, which is part of why juice remains the more common research format.

Tier 1: watermelon, a whole-food source of citrulline

Watermelon is unusual in that it supplies meaningful amounts of L-citrulline, an amino acid that raises circulating L-arginine and supports nitric oxide production through a separate route from dietary nitrate. In a 2013 study in the Journal of Agricultural and Food Chemistry, cyclists who drank watermelon juice enriched to deliver 1.17 grams of L-citrulline before intense cycling reported significantly less next-day muscle soreness than those given a placebo, with no difference in perceived exertion during the ride itself. That amount of citrulline is roughly equivalent to what you would get from about 500 to 700 grams of watermelon flesh (a large wedge to a small personal watermelon), since natural watermelon flesh contains roughly 0.2 grams of citrulline per 100 grams, concentrated mostly in the white rind. The effect size here is modest and centers on recovery and soreness rather than same-day performance, so watermelon fits better as a post-training or next-day-recovery food than as a guaranteed acute performance booster.

Tier 2: pomegranate and dark chocolate

Pomegranate's polyphenols, mainly punicalagins and ellagitannins, appear to support nitric oxide-mediated blood flow independent of the nitrate pathway. In a 2014 trial in Applied Physiology, Nutrition, and Metabolism, Trexler and colleagues gave moderately trained participants 1,000 mg of pomegranate extract (roughly the polyphenol content of 250 to 350 mL of pomegranate juice) 30 minutes before treadmill running and measured significantly greater blood flow, larger vessel diameter, and longer time to exhaustion at 90 to 100 percent of peak velocity compared with placebo. Not every pomegranate trial has replicated a performance benefit, and a systematic review in the British Journal of Nutrition notes mixed results across studies with different doses and training statuses, so the evidence is real but not as consistent as beetroot's.

Dark chocolate and cocoa work through flavanols, particularly epicatechin, which stimulate nitric oxide synthase in the vascular endothelium. The foundational human trial, by Heiss and colleagues (2005) in the Journal of the American College of Cardiology, showed that a cocoa drink providing 176 to 185 mg of flavanols measurably increased flow-mediated dilation within 2 hours. Closer to a training context, a 2015 study in the Journal of the International Society of Sports Nutrition found that cyclists who ate dark chocolate reduced their oxygen cost during moderate-intensity cycling and covered more distance in a 2-minute time trial compared with white chocolate. The catch is dose: getting 176 to 185 mg of flavanols realistically requires 30 to 40 grams of chocolate that is at least 70 percent cocoa, since flavanol content drops sharply in milk chocolate and lower-cocoa bars, and even then flavanol content varies by processing method.

Tier 3: honey, citrus, and garlic

Raw honey is the food that prompted this article, and it belongs here honestly: its evidence is real but thinner than beets, greens, or watermelon. Honey is not primarily a nitrate or citrulline source; its proposed vascular benefit comes from polyphenols such as caffeic acid and quercetin. A review by Erejuwa, Sulaiman, and Ab Wahab (2012) in Molecules summarizes evidence that honey's polyphenols reduce oxidative stress markers linked to impaired vascular function, and animal studies from the same research group have shown blood pressure-lowering effects at doses around 1 gram per kilogram of body weight. Human data on honey and acute blood flow around exercise specifically is much sparser than for the foods above, most of the supporting work is in rodents or in cardiovascular-risk populations rather than exercising healthy adults, so treat honey as a plausible, food-based addition rather than a headline performer. A reasonable serving based on the available research is 1 to 2 tablespoons (about 20 to 40 grams) taken with a pre-workout meal.

Citrus fruits contain hesperidin, a flavonoid shown to stimulate nitric oxide production in endothelial cells. In a randomized trial published in the Journal of Clinical Endocrinology and Metabolism, hesperidin treatment increased flow-mediated dilation from 7.78 to 10.26 percent compared with placebo. A 2020 trial in the Journal of Nutrition found that regular blood orange juice consumption over two weeks similarly improved flow-mediated dilation in overweight adults. A whole orange or a glass of 100 percent orange juice with breakfast is a reasonable way to apply this, though the research is built around days to weeks of regular intake rather than a single pre-workout dose. Garlic has separate blood pressure-lowering evidence: a meta-analysis in the Journal of Clinical Hypertension found garlic reduced systolic blood pressure by an average of 3.75 mmHg, with larger effects in people who started with high blood pressure, an effect attributed to allicin's vasodilating action. That research used garlic supplements standardized to allicin content more often than raw cloves, so treat raw garlic as directionally supportive rather than dosed to a specific study.

Worth a brief mention alongside these: berries (blueberries, blackberries) contain anthocyanins with similar endothelial benefits in longer-term studies, and fatty fish provide omega-3s linked to improved endothelial function over weeks of regular intake. Neither has the acute pre-workout trial data that beets, greens, or watermelon do, so they belong in a generally vessel-healthy diet rather than in a same-day pre-workout plan.

Timing, training status, and who is most likely to notice a difference

Across the nitrate-based foods (beets, leafy greens), the timing that matches the research is eating 2 to 3 hours before training, since that is how long it takes plasma nitrite to peak after ingestion. For watermelon's citrulline effect, benefits on next-day soreness were measured when juice was consumed in the hours before and after exercise, so it does not need to be timed as tightly. The research is also consistent on training status: benefits are larger and more reliable in untrained or recreationally active people than in highly trained endurance athletes, likely because trained individuals already have more efficient nitric oxide signaling and higher baseline mitochondrial efficiency, leaving less room for a food-based intervention to add on top. Effects also tend to show up more clearly in submaximal, higher-volume efforts, think longer sets, circuit-style training, or endurance work in the 5- to 30-minute range, than in single maximal lifts or very short sprints, since the underlying mechanism is about oxygen cost and blood flow during sustained effort rather than one-rep force production. If your training is mostly high-rep, moderate-intensity work, this is a reasonable category to experiment with; the effect on a single all-out heavy set is much less established. For general volume planning around that kind of training, see how much training volume actually drives muscle growth.

What the evidence does not support

A few common claims outrun the data. Beet or nitrate "gummies" dosed at 300 to 500 mg of beet powder typically supply a small fraction of the 300 to 500 mg nitrate range used in positive trials, since beet powder itself is only partially nitrate by weight. A single raw beet, a spoonful of honey alone with nothing else, or a splash of pomegranate juice in a smoothie are all directionally fine choices but are unlikely to replicate a specific study's effect size unless the portion matches what was tested. And because these foods act on blood vessels and blood pressure, not on muscle contraction directly, they will not substitute for adequate protein or training volume; they are a complement to those fundamentals, not a replacement. If you are also evaluating other widely-hyped supplements, this is a similar dynamic to the one covered in another topic where the evidence is often misrepresented in marketing, where a real, modest effect gets inflated into something categorical.

Safety notes

The most important caution applies to anyone taking blood pressure medication: nitrate-rich foods, pomegranate, cocoa flavanols, garlic, and citrus flavonoids all have blood pressure-lowering mechanisms, and stacking several of them alongside antihypertensive medication could produce additive drops in blood pressure. Anyone on hypertension medication should talk to their prescriber before making a deliberate habit of concentrated nitrate or polyphenol intake (large juice volumes especially) rather than assuming "it's just food" removes the interaction risk. Separately, beeturia, pink or red urine after eating beets, is a harmless pigment effect seen in a subset of people and is not a sign of a problem. Excess dietary nitrate is generally well tolerated in healthy adults, though the World Health Organization's acceptable daily intake can be exceeded on a high-nitrate-vegetable day, which is not established as harmful in healthy people but is worth knowing if you are eating large volumes of greens and beets together daily. None of this amounts to a medical recommendation; it reflects what the cited studies measured, and individual medical situations vary.

A worked example: a food-based pre-workout plate

Take an 85 kg lifter training in the evening who wants to apply this without buying a single supplement. Three hours before training: a roasted sweet potato, a spinach and arugula salad (roughly 100 grams of greens, landing in the 300 to 400 mg nitrate range consistent with the Hord and Foods reviews cited above), and a wedge of watermelon (around 500 grams, supplying roughly 1 gram of citrulline, in the range used by Tarazona-Diaz and colleagues). Thirty to sixty minutes before training, a small square of dark chocolate (30 grams, at least 70 percent cocoa) rounds out the flavanol contribution. None of this replaces a solid protein and carbohydrate base for the session, it layers on top of it, so it is worth checking that the rest of the day's intake is on track with a tool like the macro calculator, and pairing this kind of plate with adequate daily protein along the lines described in the research on protein intake for muscle gain.

Bottom line

Beets and leafy greens have the strongest, most consistent evidence, working through the same nitrate-nitrite-nitric oxide pathway, with arugula and spinach actually outranking beetroot in nitrate density per gram. Watermelon offers a real, food-based citrulline dose with measurable soreness benefits. Pomegranate and dark chocolate have solid but less consistent evidence through separate polyphenol mechanisms. Honey, citrus, and garlic are supportive but rest on thinner, often non-exercise-specific data. In every case, the studies used real portions, juice volumes, or gram amounts, not a pinch or a single piece of fruit, so matching the dose matters as much as picking the right food.