I Ate Sardines Every Day for a Week—Here’s What Happened

Updated: Apr. 23, 2024

There are reasons a vintage grocery like tinned fish has been wildly re-embraced...but eating sardines every day? A heath reporter's experiment led to some new diet discoveries.

Let’s get one thing out of the way: Sardines are not the most beautiful food in the world. However, it’s worth trying not to judge based on appearances here. Thanks to the COVID-19 pandemic, buying fish in a tin re-emerged as a trend when high-nutrition foods that optimize immunity also needed to have a substantial shelf-life for long stretches between supermarket visits.

These small fish deliver big on all of the above. In fact, the BBC has reported that sardines were once so abundant in the waters surrounding Sardinia—one of the world’s five blue zones where human longevity rates are highest—that this is how they got their name. Sardines are swimming with nutrients, including a good dose of the winter-starved vitamin D, more calcium than a glass of milk, magnesium and omega-3 fats, to name just a few. They’re also cooked before they’re packed in the tin, which should quell some food safety concerns. Translation: Sardines are worth a try.

At least, that’s what I told myself for a week—along with, “Adding a serving of sardines to my day fits right into my current diet.” It sort of did. I’ve been on a low-carb kick since the new year and have made an effort to add vitamin D without the use of supplements in the gloomy winter months.

I’ll admit I approached those compact silver cans with apprehension. Why? I don’t know. I’ll eat pretty much anything, and have—including crickets—but these little guys have always made me feel a tad squeamish.

My first concern with eating sardines every day was mercury, which certain types of fish contain at levels that it’s important to be educated about. With canned tuna, for instance, mercury can be a concern (it’s generally advisable to limit tuna to a weekly serving). Sardines may be less worrisome according to the Food and Drug Administration’s (FDA) list of the best fish choices. Also, Consumer Lab testing found that sardines were “very low in mercury” compared to albacore tuna levels, which came in 10 to 20 times higher.

They note, however, that because of the arsenic levels in sardines, it’s not recommended to eat more than one can per day.

sardines in a purple tinClaudia Totir/GETTY IMAGES

The health benefits of sardines

As I started to consider eating sardines every day for a week, I learned that they’re exceptionally healthy. A 2021 study published in the journal Clinical Nutrition explored the potential benefits of eating sardines for the prevention of type 2 diabetes in people over age 65 with elevated fasting glucose levels. For the study, the participants were split into two groups who both followed diabetes-friendly diets, with the exception that one group supplemented with 200 grams, or about two four-ounce cans, of sardines in olive oil per week. The sardine-eating group saw a greater reduction in both systolic and diastolic blood pressure.

An April 2023 study in the journal Frontiers of Nutrition highlighted that in some cases, sardines may even replace fish oil supplementation as a more nutrient-dense alternative with heart-healthy benefits. The researchers noted that it could be thanks in part to the anti-inflammation effects of this fish. The researchers report: “Sardines contain … nutrients which together modulate mild inflammation and exacerbated oxidative stress” that are observed in cardiovascular disease and blood pressure dysfunction.

The same research team listed the wealth of health benefits in sardines: “calcium, potassium, magnesium, zinc, iron, taurine, arginine and other nutrients.” That’s impressive nutrition for a budget-friendly fish.

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How to eat sardines

If you are going to embark on a sardine-eating journey, be aware that you will encounter multiple varieties. Like tuna and anchovies, sardines can be packed in water or oil.

Beyond that, you have so many choices for flavorings and types. You can buy sardines skinless and boneless, packed in different types of oil, and prepared with flavorings. I personally found sardines livened up with a touch of lemon, mustard, tomato sauce, or even hot sauce. My favorite preparation was to mash them like tuna salad and add a little mayo if the olive oil or added flavor wasn’t very pronounced.

I suggest for anyone who’s sardine-curious but still slightly hesitant, try a few different kinds before deciding you don’t like them.

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Unexpected effects of eating sardines every day

Increased satiety

When I ate sardines every day, I didn’t observe any immediate benefits…but I gradually realized that I would end up eating my next meal or snack much later than usual. I ate a portion of sardines at about 10 a.m. daily, which pushed my need to lunch until well after 1 p.m. Sometimes I would even forget to eat, which is a rarity for me.

The researchers in the 2023 study mentioned that eating sardines could result in a healthy reduction of appetite, a benefit supplementing with fish oil wouldn’t provide. In my case, even a small amount of sardines resulted in a long-lasting feeling of satiety. I was only eating half of a can at a time—about two ounces! I chalk that up to the contents of healthy fat, about eight grams per serving, and a noteworthy 20 grams of protein. Based on my experience, it seems sardines can be an excellent food for holding off hunger for long periods.

Increased energy and alertness

By the third day, I noticed I felt more alert. I suppose this lifted energy could have been because several gloomy, cloudy days in the Northeast finally broke up to make way for sunshine.

But considering the high vitamin D content in sardines—about 70% of the daily recommended value in three ounces—these little fish could certainly have played a role. That extra dose of vitamin D has been shown to be a mood booster and depression reducer.

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I started to like them

Around the fourth day, I started to get used to the funkiness of the fish. I enjoyed the lightly smoked preparation, and a squeeze of lemon enhanced the flavor. I could even just eat them lightly mashed with a fork, though in my research I discovered that many sardine fans swear by adding them to avocado toast.

While I didn’t think I would add sardines to my regular diet two days in, when I found the right flavor and studied all of the nutritional benefits, I will consider it. Other foods that provide vitamin D, like eggs, are high in cholesterol, and salmon can be expensive, a small serving of these little fish a few times a week could fill the nutritional gap affordably.