Most fad diets claim to be supported by scientific evidence, whether or not that is the whole truth. They often suggest that reducing carbohydrates and increasing meat consumption or strictly consuming liquids will lead to rapid weight loss. Some of these diet trends gain popularity before sufficient scientific evidence is available to confirm their effectiveness or safety. The all-sardine diet, a recent internet fad, falls into this category.
This weight-loss strategy involves consuming tinned sardines exclusively, along with water, tea, and black coffee. Some individuals adhere to it for a few days, while others commit to the diet for several months.
Origin and Popularity
The sardine-only diet gained popularity in 2023, thanks to Annette Bosworth, known as Dr. Boz on YouTube. Slate reports that Bosworth has been a vocal advocate for other low-carb, high-protein keto diets. In her videos, Bosworth has promoted the benefits of the diet, asserting that the fish, rich in omega-3s, vitamin E, and calcium, can "surge your ketones" when consumed exclusively for three days. This process induces ketosis, where the body derives energy from fat instead of glucose, leading to weight loss.
Whether her claims are credible is debatable, especially considering that she was stripped of her medical license in 2015.
Anecdotal Successes and Drawbacks
Some participants have taken the diet to extreme levels. For instance, one woman reported losing 35 pounds by consuming only sardines for three consecutive months. However, the benefits and drawbacks appear to be subjective. Kendra Von Esh, a YouTuber, described her experience with the diet as resulting in an unfortunate bout of diarrhea after just two days. Similarly, blogger Courtney Luna admitted that she had to cut her 10-day fast short when her body signaled that she "should stop," yet she still felt it was worthwhile.
Read also: The Hoxsey Diet
Expert Opinions
Experts hold differing views on the sardine diet. Eating Well notes that the nutrients found in sardines, such as calcium, potassium, magnesium, iron, and zinc, can support bone health, prevent type 2 diabetes, and promote brain health. However, the American Heart Association recommends a more moderate approach than consuming only fish for three consecutive days, advising people to consume fish twice a week.
Beth Czerwony, a dietitian at the Cleveland Clinic, cautioned that the all-sardine diet could elevate mercury levels, which can be hazardous. Dr. Masarat Jilani noted that while sardines provide numerous nutrients, they lack other essential components of a balanced diet. According to The New York Post, Jilani stated that sardines contain no fiber, which is crucial for gut health and digestion, and a diet solely based on sardines could lead to constipation. Additionally, the canning process often involves preserving sardines in salt or oil, leading to excessive sodium intake, which can raise blood pressure and strain the kidneys.
Nutritional Profile of Sardines
Sardines are indeed a nutritional powerhouse when consumed in moderation. They are rich in various nutrients, including:
- Omega-3 fatty acids: Beneficial for heart and brain health, and can reduce inflammation.
- High-quality protein: Supports muscle maintenance and promotes satiety.
- Calcium: Especially in canned sardines with bones, supports bone density and the nervous system.
- Vitamin D: Important for bone health and immunity.
- Vitamin B12 and selenium: Key for metabolism and thyroid function.
Potential Risks and Side Effects
Limiting your diet to a single food like sardines for extended periods can have negative health effects. According to Grace Derocha, a registered dietitian and spokesperson for the Academy of Nutrition and Dietetics, relying on one food alone poses serious nutritional and health risks.
- Nutrient Deficiencies: Sardines lack key nutrients such as vitamin C, fiber, magnesium, and certain B vitamins, which are critical for immune function, digestion, energy production, and overall health.
- Antioxidant Deficiencies: Long-term adherence to a sardine-only diet could lead to deficiencies in antioxidants like vitamins A and E, and phytochemicals, which protect against chronic diseases.
- Excessive Nutrient Intake: Consuming sardines exclusively can lead to excessive intake of certain nutrients, such as sodium, which can increase the risk of high blood pressure and cardiovascular disease.
- Mercury Exposure: Although sardines are lower in mercury compared to larger fish, a diet exclusively made up of fish still raises concerns about cumulative exposure to heavy metals and other environmental contaminants, especially over long periods.
- Short-Term Side Effects: Some people might experience short-term side effects, such as diarrhea, fatigue, mood changes, and constipation.
Personal Experiences
Jane Crummett, of Mint Hill, North Carolina, doesn’t consider her eating pattern a “diet.”“To me, a diet insinuates a beginning and an end. This is my lifestyle and I have no intention of introducing plants back into it,” she recently told Fox News Digital.
Read also: Walnut Keto Guide
Before her months-long sardine-only lifestyle, Crummett was following a “zero carb/carnivore” diet - eating no carbohydrates at all. She also skipped dairy because she “finds it inflammatory,” she told Fox News Digital.
She ended her dalliance of eating only sardines on September 30 after 135 days. While only eating sardines, she lost 35 pounds over three months, she said, and felt better overall.
“My pain has resolved” and her inflammation has decreased, she told Fox News Digital. Despite her restrictive diet, Crummett said she is healthy and sees a doctor regularly. She plans on reintroducing other meats back into her diet under the guidance of a doctor.
“My ultimate goal is to have sardines for breakfast every day with MCT oil and incorporate normal beef, pork and/or chicken back into my diet,” she told Fox News Digital. Crummett is not alone in embracing a sardine-only diet.
Last year, Patti Bodner, a 67-year-old Florida grandmother, told Yahoo Life that she lost weight while following a three-day sardine challenge. She also said her blood sugar levels went back to normal, and she was able to stop using the insulin she was taking for type 2 diabetes.
Read also: Weight Loss with Low-FODMAP
It is not clear if she was able to maintain these changes after the end of the three-day experiment.
The Sardine Diet as a 3-Day Challenge
This challenge, as the name suggests, involves eating only sardines in oil for 72 hours. You are also allowed a carb-free hot sauce or other seasoning, salt, water and black coffee.
This trend was popularized in 2023 by Annette “Dr. Boz” Bosworth, MD, a Florida-based internist who is an advocate of low-carb, high-protein keto diets.
Is the Sardine Diet Sustainable?
Single-food fad diets are restrictive, unsustainable, and not healthy, as they usually lack key nutrients, Taub-Dix says.
The monotony and rigidity of eating one thing could lead to binging on other foods, and it’s also likely not a sustainable way to eat, she adds.
Moderation is Key
Sardines are “a nutritional powerhouse in moderate amounts,” says Begdache. “They are one of the best animal proteins you can eat.”
"You don’t need to eat only sardines to get these benefits. But they can easily be part of a balanced diet,” says Hadley.
Zerner recommends eating a 3-ounce serving of fatty fish, like sardines, twice a week. Pair the fish with vegetables and whole grains for a more balanced meal, Hadley adds.
Taub-Dix also suggests incorporating a variety of protein sources, such as other types of lean meat, tofu, or beans.
Tips for Incorporating Sardines into Your Diet
When purchasing sardines, Dr. Begdache suggests looking for low-sodium products (or rinsing the sardines to minimize salt) or choosing sardines packed in water, which tend to be lower in calories than those packed in oil.
Also, eat the bones and skin to get the most nutritional value, she says.
Precautions
It’s important to talk to your doctor before trying a diet like this.
People with kidney disease, high blood pressure, or gout should be cautious about adding sardines to their diets, Taub-Dix says.
My Personal Experience
I never thought eating only sardines would lead to dramatic weight loss until I tried it myself. After just eight days on this unconventional diet, I shed an impressive 6 kilograms. After struggling with conventional diets, I stumbled upon viral stories of people experiencing rapid weight loss by consuming only sardines. The high protein, healthy fat combination seemed scientifically plausible for quick results. My protocol was simple but strict: canned sardines in water, black coffee, and plenty of water. I consumed approximately 4-5 cans daily, spacing them throughout the day.
By day three, I noticed my energy levels stabilizing without the usual afternoon crashes. My skin appeared clearer, possibly from the omega-3 fatty acids that sardines provide. My body essentially entered a state similar to ketosis, burning stored fat for energy like a car switching from gasoline to reserve fuel. After eight days, I slowly reintroduced other foods, starting with leafy greens and berries. This gradual approach helped minimize rebound weight gain.
Like sprinting versus jogging, this diet offers quick results but isn’t sustainable long-term. While I don’t regret my experiment, I’ve since found more balanced approaches incorporating sardines alongside diverse nutrients.
Another Personal Experience
In July 2023, I had a minor operation, which meant that I couldn't do much for the following few days. By fasting, my aim was to speed up my recovery process. As humans, all the food we eat uses a lot of our body's resources. By eliminating food, the aim is for our bodies to fully focus on healing and recovering.
I did not want to focus on losing any weight, but my weight loss on the journey was a representation of my sticking to the diet.
On the first day, I weighed 169.5 lbs. Each tin had 225 calories, and I ate two tins. I definitely did not feel full afterward, but at the same time, I didn't feel hungry.
By lunchtime, I noticed that the lack of carbs made me feel very weak, I could barely open a tin of sardines. Dr. Boz also said that during the diet, you can season your sardines. She suggests using low-fat seasonings like black pepper and mustard, but I ate it straight away without seasoning it.
If you're going to try the sardine fast out for yourself, my tip would be to not make eye contact with the sardines when you're eating them, because I looked at one a little too long and it made me feel sick.
By day two of the fast, I realized that I did not like sardines. But seeing as I was halfway through the fast, I decided to continue it.
My energy levels were good considering I just had minor surgery and was supposed to take it easy and rest. I was also unable to walk very far but I found myself having increased mental focus and clarity, enabling me to spend most of the day catching up with work on my computer. I took it easy during the fast as I was recovering. I also slept very well in comparison to when I was doing other fasting methods like the water fast.
On day three of the fast, I decided to season the sardines with a serving of Nando's hot sauce, which had 0.5 grams of carbohydrates in the serving. It did not taste good, and I still struggled to eat the sardines but I felt like I was entering ketosis. I felt energized, focused, and a lot better in general.
After I finished the fast, I weighed 165.7 lbs. I lost four pounds in three days, as well as one percent body fat, according to my scales. In total, I ate 16 cans of sardines, which amounted to 3,728 calories. Split between the three days, that was 1,252 calories a day, which explained my weight loss.
I found this fast easy compared to some of the others that I had done. The only main drawback for me was that I did not like sardines whatsoever. As mentioned previously, the main reason why I wanted to do this fast was to speed up my recovery after surgery, and I felt very good at the end of the fast.
Usually, when I'm feeling under the weather, I like to gorge on chocolate and junk food to make myself feel a little better. Doing this fast helped me to avoid that and helped my body focus on healing and recovering.