When his son Lelea was diagnosed with type 1 diabetes at the age of seven, Ben Fonua said the family's lives were changed "overnight".
While he now said the diagnosis was perhaps a "blessing in disguise", Fonua acknowledges the family - who hail from Tonga - lacked awareness of the nutritional value of the food they were eating.
"From [the diagnosis], we [became] very aware of our nutrition values of what we consume; whether it's food or drinks."
Diabetes is a growing problem within the Pasifika and Māori communities, with instances of the disease three times higher than among other New Zealanders.
Roughly 323,700 people are estimated to have diabetes - type 1 and 2 - in New Zealand, according to Te Whatu Ora findings from the 2023 Virtual Diabetes Register.
"Diabetes is a major cause of premature death and morbidity and disability, not only for Pacific people since they are proportionately most affected, but is a concern of almost all New Zealanders," University of Auckland epidemiologist Dr Simon Thornley said.
The Fonua family spent some time living in Arizona, in the US, where Lelea was a youth ambassador for the American Diabetes Association (ADA).
It was here they fell in love with authentic Mexican food.
"We loved the culture, the people and the flavours," Ben said.
Owner of Tokos Tacos, Ben Fonua and son Kisione Lelea Hikulangi Kae Kaea Fonua. Photo: RNZ / Marika Khabazi
But eating out as a diabetic has its challenges, Lelea pointed out: "there's not a whole lot of options available that's not going to affect your sugar levels".
"Most of the foods that are available have a chunk load of carbs and it's hard to go eat out without having those options in front of you."
With a planned return to NZ for the Fonua family, the idea for Tokos Tacos was born.
"We knew at the time NZ was missing authentic and good tacos," Ben said, explaining his plan was to create an alternative low-carb menu to cater to diabetic customers like his son.
With diabetes a growing problem within Pasifika communities, Lelea said having the option of 'low carb' on the menu "is the best way" for his family business to play their part in raising awareness and taking it on.
"We wanted to give the option that yes, this is low carb but also yes it tastes good," he said.
Through his work with the ADA, Lelea and Ben were able to connect with Dr Thornley and fellow University of Auckland epidemiologist Dr Gerhard Sundborn, who had also travelled to America to work on reducing sugary drinks in public schools under 'Dr Fizz'.
"They had highly recommended a ketogenic menu for Tokos Tacos," Ben said.
Tokos Tacos Photo: RNZ / Simon Rogers
Ketogenic dietary strategy and restricting sugar intake is particularly useful in improving glycaemic control for type 1 diabetes, Dr Thornley said. "More broadly, in terms of reducing overall metabolic health risk."
Dr Thornley said reducing sugar and refined starch intake was important for reducing glycaemia for those who had or were at risk of diabetes.
"In some cases, restricting carbohydrates has shown reversal of [type 2] diabetes.
He concedes there has been some controversy around ketogenic diets and restricting carbohydrates to manage diabetes - "many diabetes services in New Zealand do not currently recommend it" - but says it's becoming "more common" for people to use such a strategy to improve diabetic control for both type 1 and 2.
"For type 1 diabetes, it certainly does not mean abandoning insulin treatment altogether – which may lead to ketoacidosis - but rather usually means lower doses of insulin than with a high carbohydrate dietary regime."
Dr Thornley points to a study of around 300 type 1 patients who followed a low carb diet and experienced a low rate of diabetes-related emergencies each year, compared to other published studies of type 1 people following a conventional diet.
Taking the advice from Dr Thorney and Dr Sundborn, Ben Fonua created a low-carb fish taco to separate the business from your 'normal' birria taco.
"The fish tacos are very unique to us; fish tacos aren't generally a birria, it's usually beef."
The taco is ketogenic as it only contains six grams of carbs but is high in protein. And, they say, it is their most popular item.
Tokos Tacos started as a food truck, but its success has allowed the Fonua's to expand to a takeaway shop in Auckland's Avondale, and has allowed the family - which includes Ben's wife, children, brother, nieces and nephew - to work together every day.
"I love it," Ben said. "It's a blessing and it's special."
Fonua likens the Mexican culture to his own Tongan heritage, whereby family is significant and "community is very important" - "similar to the Polynesian way of uplifting each other".
"We want people to know we are Polynesian, Tongan descent - but at the same time we invite all cultures, because we are a fusion."
Ben said the family treated their customers as if they were "serving our parents".
"We want to incorporate the best of what NZ has to offer - but the Tongan part of it, we want to make sure we preserve that and pass it on for the next generation."
Lelea said 'Toko Tacos' represents brotherhood, family and "amazing Mexican food and vibes".
"Ma'ata ma Tonga."