But people around the 24-year-old, who is admittedly at the higher end of the range, call her "sumo."
Nguyen, who used to love munching on snacks and sipping boba milk tea in the evening, admits: "I act as if I don't care, but I'm still a girl and such a label triggers in me a subconscious fear of becoming fat."
The office worker in HCMC's District 7 tries not to let others’ negative comments bother her, but has nevertheless grown tired of people’s criticism.
Her weight and eating habits have become "semi-public" with family members often criticizing her appearance during the Lunar New Year, and friends constantly pushing her to lose weight.
As a result her self-esteem has plummeted, she says.
The shame and guilt caused by others has pushed her into action.
She spends the better part of the day in front of a computer screen and is not physically active, and so has embarked on a strict eat-clean diet in the hope of losing two to three kilograms this summer.
"I am not striving for slender graceful legs. I just hope to be able to tone up a bit and feel more confident about wearing skirts, crop tops and tight clothes when going out."
One doesn’t hear about too many cases of extreme thinness on local media, and popular culture has in a decade or so moved from a feminine ideal of a cute, chubby face on a slender body to suggest sweet girlhood to strong-willed sexiness indicated by an edgy V-shaped face on a curvy Korean-inspired S-line body.
Nonetheless, these days many people, men included, are pulling up their sleeves to run on treadmills or, like Nguyen, going on a diet to shed as much fat as possible, especially after accumulating some during Covid-19 lockdowns.
Losing weight all the rage
At her workplace, Nguyen Thi Nhu Quynh, 33, a HCMC accountant, says the talk every morning before work and during lunch is about what to eat to lose weight.
"We often share clips that show how to cook easy, delicious dishes with little fat that can be taken to work or weight loss tips from people who have succeeded in losing weight."
Quynh gained an extra three kilograms during the pandemic.
As many of her colleagues have lost weight by practicing yoga, she has registered for a yoga course at the Women Cultural House in District 3 for VND340,000 (US$15) a month.
"I feel envious of people posting their photos before and after losing weight on Facebook. They both remind and inspire me to lose weight myself.
"I’m really scared of that word 'fat'. I hate to be called 'fat'."
Quynh’s sensitivity about her body reflects a common concern among Vietnamese in recent years, even before the pandemic forced people to stay indoors and put on weight.
For instance, a 2015 survey titled ‘Vietnamese on a diet’ done by market research company Q&Me found that 79 percent cared about their body shape and 53 percent thought they were "a bit fat."
More than 65 percent had tried to lose weight, with most seeking to lose three to five kilograms. Women wanted to lose weight to have more confidence in themselves, and preferred eating healthy, while men linked lower weight with good health and sought to achieve it through exercise.
Truong Quoc Tuan, 38, a HCMC businessman, joined a gym near his company in District 4 after the Lunar New Year because he felt "heavy" and did not want to gain more weight.
Tuan’s goal is modest. He is not following any draconian workout or diet regime to achieve some masculine ideal. He says he only wants to be a little slimmer to feel a bit lighter and avoid diseases in future.
Gendered pressure
Though men do care about their looks and bodies, it has always been more of a woman’s lot to look attractive and fit, either to fulfill age-old patriarchal expectations -- as in the Vietnamese proverb that says a woman with a bee’s, or small, waist is good at raising children and pleasing husbands -- or conform to fleeting market trends.
Thuy Nhu, owner of POPO Concept, a women’s fashion shop in Binh Duong Province near HCMC, says the "beautiful sex" is always under pressure to look "slim and dainty."
At the moment the most popular styles at her shop are getting tighter, revealing and sexy.
"The sizes are getting smaller and smaller," she says.
At 19, Tran Thi Nhu Quynh of Hanoi’s Dong Da District has already experienced lots of gendered expectations about how to look. Quynh says her family always tells her to stay slim in order to "get a boyfriend and husband."
When she was in high school, her mother would often tell her to control herself and eat less when she gained a little weight during the Lunar New Year.
"My mother associates slim with healthy.
"Sometimes I thought she overreacted, for example by immediately cutting meat and increasing vegetables in our meals after Tet. But I understand she does it only for my good."
She says as a result, whenever she sees food, her mind instantly calculates how many calories it contains.
Nguyen stands naked on a scale on an empty stomach every night to check her body weight, hoping she would one day come down to 55 kg.
On occasion, she even skips breakfast and lunch, but it only exhausts her and makes it harder to work.
"Sometimes my colleagues go out for Korean BBQ or hotpot. But I turn down their invitation because I don’t want all of my efforts of the past few weeks to go down the drain."