I ate popular ‘health’ food to lose weight… but it was poisoning me

Nasha Montgomery was looking to lose weight and began following a healthy diet, incorporating what she thought was a powerhouse food.

A mainstay in her plan was canned tuna – promoted as a healthy staple for its high-quality protein, omega-3 fatty acids and essential vitamins and minerals. 

The office worker from Alabama would meal prep salads with tuna and eat it in sandwiches, with crackers for breakfast and lunch and as a snack at work every day.

On average, Montgomery, 29, would consume about six cans of tuna a week – each ranging between 5 and 12 oz. This meant she was eating between 2 and 4.5 lbs of tuna per week.

What Montgomery didn’t realize, was that tuna is high in mercury – a neurotoxin. Mercury is present in all fish, but can be at concerning levels in tuna, especially depending on the type, because they are predatory fish that accumulate a lot of mercury through their diet.

Montgomery said she mainly consumed albacore tuna, which has some of the highest levels of mercury among the fish varieties.

Most people can safely eat just 5 oz of albacore per week – Montgomery was eating up to 14 times what is considered a safe amount. 

After about four months on the diet, she began experiencing muscle cramping, hair loss and a metallic taste in her mouth – a hallmark symptom of mercury poisoning.

At first, she blamed her symptoms on stress as she had just started a new job. But following a heavy metals blood test, she claims high levels of mercury were found in her body and she was diagnosed with suspected mercury poisoning.

Mercury poisoning can cause serious neurological damage and the FDA and EPA urge people to limit their fish intake because of it – pregnant women are advised to avoid fish altogether.

Symptoms include memory loss, irritability, tingling limbs and changes in vision, taste or smell. The toxin can also travel to your heart and kidneys, causing damage to the organs.

To treat the toxicity, doctors will administer chelation therapy, which removes heavy metals from the body through fluid in an IV.

Detailing her ordeal in a TikTok earlier this month, Montgomery said she would meal prep tuna with mayo, onions and relish and ‘eat it throughout the day for breakfast, snacks, lunch’ and even again for dinner if she had leftovers – going through about six cans per week.

‘It became a theme [at work], that because I was eating so often, my colleagues would call it “tuna time” instead of lunch time,’ she said.

‘Around the 4.5 month mark is when I noticed major symptoms. I started to feel sick, tired all the time, my muscles were weakening and cramping.

‘My hands and feet were tingly and numb and my hair was falling out. On occasions I started to have a metallic taste in my mouth, too.’

She went to the doctor for a regular physical, and the blood tests didn’t reveal anything out of the ordinary. But when the symptoms continued, doctors inquired about her diet and she mentioned she was eating a lot of tuna.

That’s when doctors ran the heavy metals panel. 

‘I was in shock as I thought I was doing something right by eating the tuna as it was healthy and the things I was eating the tuna with were also healthy,’ Montgomery said.

‘I felt like I was doing right by myself, but too much of a good thing can always backfire.’

To allow her levels to return to normal, Montgomery had to go on an eight month detox from the seafood and now only eats tuna about once a month. 

‘I was detoxing like I was addicted to it,’ Montgomery said.

‘I’m very careful now about my fish choices. It took me about six to eight months to get my body back to normal.

‘Sometimes I do feel tingly or numbness in my fingers and feet but aside from that I haven’t experienced any long-term effects [from my mercury poisoning].’

Following her experience, Montgomery is eager to raise awareness about the dangers of eating too much tuna.

‘One thing I would say to people eating tuna all the time is I’d advocate for them to be more aware,’ she said.

‘Especially when it comes to something seemingly healthy like tuna, you want to make sure you’re balancing those things out.

‘It’s easy to overlook subtle symptoms, but if something feels off, it’s important to slow down, pay attention, and take care of yourself.’