A man lost 10 pounds in a month eating nothing but sandwiches to prove you shouldn't be scared of bread

• Personal trainer Sean Casey ate nothing but sandwiches for 30 days and lost 10 pounds.
• There is nothing magical about sandwiches — Casey was just in a calorie deficit.
• He wanted to show people who want to lose weight don't need to fear bread.

When Sean Casey first tried to lose weight as a teenager, he believed the myth that you have to cut carbs to do it. He now knows that's not the case.

Now 23, the personal trainer from Banbridge, Northern Ireland, decided to spread this message to the millions of followers he's gained online by making content that demystifies the world of fitness and fat loss, by eating nothing but sandwiches for 30 days while in a calorie deficit, and losing 10 pounds (4.5 kilograms) in the process.

Casey wanted to remove the fear and anxiety some people have around certain foods, particularly bread, when it comes to weight loss, so they understand that no food should be feared.

Experts have previously told Insider that there's no such thing as a "good" or "bad" food, no food is inherently fattening, and carbs are an important energy source that can help with fat loss, although a person's weight isn't the only signifier of their health.

"There's a lot of fear and demonization," Casey told Insider. "People think that there are particular foods that will make them fat, and it creates a lot of unnecessary stress and worry and anxiety around food."

Casey made sure he was in a calorie deficit

Casey acknowledges that he lost weight faster than is considered safe for people without lots of body fat to lose — experts recommend smaller calorie deficits and gradual weight loss for sustainable results — but he decided to go into a steep calorie deficit to make his point.

He calculated that his body burns around 3,000 calories each day, so he consumed three to five sandwiches daily, as well as low-calorie drinks, which added up to between 2,300 and 2,500 calories. The relatively extreme deficit got hard towards the end as his hunger ramped up, he said.

He didn't strictly track his protein intake, which is important for maintaining muscle while losing fat, but ensured he was getting a good hit in pretty much every sandwich, he said.

Casey continued his workout regime as normal throughout the experiment.

Casey didn't get bored of sandwiches

What does and doesn't constitute a sandwich can get blurry. But Casey decided he would keep things strict and simple: everything he ate had to be between two slices of bread, and burgers and wraps weren't allowed. And from there, the possibilities were endless.

Casey was surprised that he didn't get bored of sandwiches, and barely ate the same one twice. He kept it interesting by eating a mixture of savory and sweet sandwiches, toasted sandwiches, and sandwiches cooked in an air fryer.

His favorite was a pizza-inspired sandwich: Casey spread tomato sauce on one slice of bread and topped it with some cooked chicken, cheese, and the second slice of bread, before topping that with more tomato sauce and cheese and cooking in the air fryer.

"It was actually better than a normal slice of pizza," Casey said. "It was really, really good with the two layers."

Casey ate sandwiches containing all sorts of ingredients, from tuna, cheese, mayonnaise, and onion, to Mars bar and apple, he said. But, he always kept an eye on his calories, using ingredients such as light cheese, low-fat sauces, and low-calorie bread.

Depending on the bread and filling, a sandwich can be a nutritionally balanced meal, providing carbs, fiber fat, protein, and micronutrients.

But Casey acknowledged his sandwich-only diet was not as nutritious as a healthy diet should be. Although Casey ate wholemeal and sourdough bread from time to time, he lacked fruits and vegetables, but stuck it out for the 30 days to make a point.

"I wanted to have some fun with it and try lots of different sandwiches that weren't necessarily the most nutrient-dense, and prove that you can do that and still achieve your goals," Casey said. "But in the long run, I wouldn't recommend anyone eat like that, and I certainly won't eat like that in the long run."

Experts have previously told Insider that people should strive for a predominantly whole foods diet that contains a balance of protein, carbs, and fat, and plenty of whole grains, fruit and vegetables. However, you should incorporate all foods you enjoy into your diet in moderation.

You don't need to fear any foods

At the end of the experiment, Casey had lost fat while maintaining the muscle he had spent years building, making it more visible.

But Casey stressed that there is nothing special about sandwiches as a weight loss food, he was simply in a calorie deficit.

"I didn't lose weight because I was only eating sandwiches," Casey said. "I lost weight because I was controlling my calories."

Casey documented the whole experiment on his social media accounts and said he's received numerous messages from followers saying his experiment has helped them feel more relaxed about eating bread and sandwiches.

"More people are viewing the sandwich as something that's actually a positive, not just for taste and happiness, but a positive for their weight loss journey," he said. "Long live bread."