The health check report from work says BMI 23.8, with the word “normal” next to it. A few lines below, fasting blood glucose and blood lipids are highlighted in yellow. The dress pants bought for Tet (Lunar New Year) the year before last now only button up if you suck in your stomach, even though the bathroom scale has crept up just about two kilos over the past few years.
BMI cut-offs are lower for Asians
BMI is your weight (kg) divided by the square of your height (m). At 1.60 m tall and 61 kg, your BMI is about 23.8. The international table only counts overweight from 25.
In 2004, an expert consultation of the World Health Organization reviewed the evidence from many Asian countries. The panel found that in Asian people, the same BMI goes with a different amount of body fat and a different disease risk than in Europeans. Quite a lot of people already have a high risk of type 2 diabetes and heart disease while their BMI is still below 25. The panel proposed that public health action start from the first cut-off point, 23.
In Vietnam, doctors usually read adult BMI using the table for Asian populations:
- From 23 to 24.9: overweight;
- From 25 to 29.9: obesity class I;
- 30 and above: obesity class II.
By this table, the report at the start should already have said overweight. Someone who has lifted weights for years can have a high BMI and still a flat stomach, because BMI cannot tell muscle from fat.
What your waist adds to the picture
In 2009, six international organizations working on diabetes, heart disease and obesity agreed that any three of five abnormalities are enough to diagnose metabolic syndrome. The five are abdominal obesity, raised blood pressure, raised triglycerides, low HDL and raised fasting blood glucose. Waist circumference is considered a useful first screening tool, while the cut-offs depend on ethnicity. For Asians, the usual cut-offs are 90 cm for men and 80 cm for women.
Dang and colleagues (2022), together with the National Institute of Nutrition, measured 4,701 adults in four regions of the country to find the body measurements that help pick out metabolic syndrome. BMI was already worth noting from about 22.4 in men and 23.6 in women. The waist-to-height ratio had cut-offs of 0.53 in men and 0.51 in women, meaning a waist of roughly half your height. The authors advised Vietnamese health workers to use lower cut-offs than the international guidelines so as not to miss anyone.
To measure at home, stand up straight in the morning before eating, breathe out gently, and wrap the tape snugly against your skin, level all the way around your waist. If you are 1.60 m tall, half your height is 80 cm, the same as the waist cut-off for women.
What keeps the weight on
In adults, short sleep goes with a higher risk of obesity, with an odds ratio of about 1.55. This figure comes from a meta-analysis by Cappuccio and colleagues (2008) that pooled 30 studies with more than six hundred thousand people. For each hour more or less of sleep, BMI differed by about 0.35. Most of the data come from cross-sectional surveys, so they cannot yet show which is the cause. If you work night shifts, care for a young child or are used to staying up late in front of a screen, the doctor will ask about your sleep before your eating. A few habits that help you sleep deeply are in our article on sleep.
Some people open the fridge at eleven at night without being hungry, after a stressful day or an upsetting phone call. Eating at that moment is the body’s way of calming itself.
In the medicine cabinet at home, some antidepressants, anti-seizure medicines and long-term oral corticosteroids can cause weight gain or increase appetite.
In women, infrequent periods together with acne, extra hair growth and a waist that keeps getting bigger may be linked to insulin resistance in polycystic ovary syndrome (PCOS). Hormonal questions can only be settled with lab tests, and our article on polycystic ovary syndrome (Vietnamese) covers this in detail. People who have been on many rounds of dieting, or who skipped rice or breakfast for years, often say they feel tired, get cramps and sleep fitfully, and for them the doctor also looks into micronutrients.
Weight gain with which signs needs lab tests
Weight that goes up quickly over a few weeks, with a puffy face, swollen legs, exhaustion and feeling cold, calls for thyroid tests and a check of the heart and kidneys. Being very thirsty and urinating a lot should prompt an early blood glucose test. Loud snoring, a family member noticing that you sometimes stop breathing in your sleep, and nodding off wherever you sit during the day mean you should be checked for sleep apnea. If you have gained weight clearly since starting a new medicine, bring that blister pack to the doctor who prescribed it and ask, and don’t stop the medicine on your own.
When you come for a consultation
The first question from Dr. Dinh Ngoc Duc (MD, MSc in Traditional Medicine) is usually when your weight started to change and what was different in your life at that time: a new job, having a baby, switching to shift work, starting a medicine. Then the doctor measures your waist and blood pressure, and looks at the blood glucose and lipid results you bring.
Muscle testing helps the doctor see which factor is stronger in each person. When you recall standing in front of the fridge late at night and a normally strong muscle suddenly goes weak, the doctor notes that stress is probably helping to keep the weight on. The micronutrient part is checked the way our article on the health triangle describes. Blood glucose, blood lipids and the thyroid, on the other hand, the doctor reads from your lab results.
If you often wake in the middle of the night and have to eat something before you can fall back asleep, the doctor uses acupuncture to settle your sleep.
Some people feel heavy, with a full stomach after meals, slightly puffy eyelids in the morning, loose stools, and a swollen tongue with tooth marks. Traditional medicine thinks of Spleen deficiency giving rise to dampness (脾虚生湿 / 脾虛生濕, pí xū shēng shī), and the doctor prescribes an herbal decoction to strengthen the Spleen and clear dampness, choosing the herbs according to that person’s own pulse and tongue. If you don’t move much, the doctor also shows you exercises to keep your thigh and buttock muscles strong, which you can do at home.
The clinic does not set a target number of kilos and does not hand out a standard meal plan. The doctor focuses on what is getting in the way for each person, whether sleep, stress or micronutrients, so the body can adjust itself from there. Your waist is measured again at follow-up visits so we can see together how your body is responding.
Worth keeping
- Measure your waist once a month, at the same time and with the tape in the same place; there is no need to measure every day;
- If your waist is more than half your height, ask your doctor about blood glucose and lipid tests;
- Read your BMI using the table for Asians: from 23 is already overweight;
- Write down when you go to sleep and wake up for one week before changing your diet;
- If you have gained weight since starting a new medicine, tell the doctor who prescribed it, and don’t stop it on your own.
References
- WHO Expert Consultation (2004). Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. Lancet 363(9403):157-63. https://doi.org/10.1016/S0140-6736(03)15268-3
- Dang AK, Truong MT, Le HT, Nguyen KC, Le MB, Nguyen LT et al. (2022). Anthropometric Cut-Off Values for Detecting the Presence of Metabolic Syndrome and Its Multiple Components among Adults in Vietnam: The Role of Novel Indices. Nutrients 14(19):4024. https://doi.org/10.3390/nu14194024
- Alberti KGMM, Eckel RH, Grundy SM, Zimmet PZ, Cleeman JI, Donato KA et al. (2009). Harmonizing the metabolic syndrome: a joint interim statement of the International Diabetes Federation Task Force on Epidemiology and Prevention; National Heart, Lung, and Blood Institute; American Heart Association; World Heart Federation; International Atherosclerosis Society; and International Association for the Study of Obesity. Circulation 120(16):1640-5. https://doi.org/10.1161/CIRCULATIONAHA.109.192644
- Cappuccio FP, Taggart FM, Kandala NB, Currie A, Peile E, Stranges S, Miller MA (2008). Meta-analysis of short sleep duration and obesity in children and adults. Sleep 31(5):619-26. https://doi.org/10.1093/sleep/31.5.619
