South Asians, including patients with ancestry from India, Pakistan, Bangladesh, Sri Lanka, Bhutan, Nepal, and the Maldives make up about 25% of the world population. Over 5 million South Asians live in the US and over 2 million live in Canada. An overwhelming amount of evidence exists regarding our much higher risks of diabetes and heart disease. As just one example, in one study, South Asians were at 3.1x as likely to develop diabetes, 1.34x as likely to develop high blood pressure, 1.8x as likely to develop ischemic heart disease than white Europeans in the United Kingdom. This is despite the fact that the two groups had similar body mass indexes (BMIs) and the South Asians had lower blood pressures, lower total cholesterol levels, smoked less, and had lower alcohol consumption [14]. Weight management for South Asians is vital as a preventative measure as discussed in the following sections of this page: Genetics, epigenetics, nutrition, psychology, activity, and treatment criteria for medications and surgery.

South Asian Genetics

According to one study looking at the origins of low lean mass in South Asians, South Asian skeletons spanning the last 11,000 years have low lean mass and may represent long-term adaptations to ecological pressures [13]. Other studies have found that on average, South Asians have 3-5% higher body fat than Europeans, [2] higher visceral fat (the bad fat that wraps around organs in the abdomen and increases our risk of other metabolic diseases) [5] and overall body fat [6] at any body mass index (BMI) level.

Studies have shown higher lipoprotein (a) levels in South Asians [15]. Elevated Lp (a) levels are an independent risk factor for heart disease [16]. Lp(a) is a subclass of low-density lipoproteins (LDLs) and risk for elevated levels is strongly genetically linked. We also have larger fat cells (adipocytes), fewer ‘good’ fat cells, and an increased risk of metabolic syndrome [7]. We are genetically predisposed to develop type 2 diabetes [3,4]. In one study looking at South Asians in the United States, the risk of diabetes is more than 2.5X higher even at a lower body weight [1].

This is why our BMI criteria need to be different than the standard BMI criteria. For Europeans, a BMI of 18-24.9 is considered healthy, a BMI of 25 to 29.9 is considered overweight and a BMI of 30 and higher is considered obese. In South Asians, because our genes lead to more visceral fat storage in our midsections, our BMI cutoffs are much lower. A BMI of 18-22.9 is considered normal for most South Asians while a BMI of 23-24.9 is considered overweight and a BMI of 25 or over is considered obese.

In terms of waist circumference (WC), a waist circumference of <100 cm is considered normal in European men, and a WC of <90 cm is considered normal in European women. In South Asians, the cutoffs are about 10 cm lower for each category. In other words, men should ideally have a WC of <90 cm (35 inches), and women should have a WC of <80 cm (31.5 inches).

Being overweight or obese increases your risk of other metabolic conditions such as insulin resistance, pre-diabetes, diabetes, high blood pressure, fatty liver, gout, and high cholesterol. In addition, being overweight or obese can contribute to mechanical conditions such as gastric reflux, sleep apnea, and osteoarthritis. Finally being overweight or obese can contribute to mental health conditions such as depression and anxiety.

South Asian Epigenetics

Epigenetics is the study of changes in humans caused by changes in gene expression rather than changes in genes. These gene expression changes are a result of the prenatal environment such as the nutrition or weight status of the mother. South Asian mothers often have low weights which leads to lower birth weight infants. A study has shown that people born with a low birth weight who gain weight quickly during their childhoods may be more prone to central obesity and cardiometabolic disease in adulthood [9]. In another study, higher birth weight infants were found to have more lean mass but not fat mass as adolescents. [12]. Unfortunately, many South Asians are born with low birth weights, putting them at greater risk for central obesity and lower fat-free mass which is often observed in adult South Asians.

South Asian Nutrition

There are several important differences between South Asian and European nutrition. South Asians can eat a disproportionate amount of simple carbohydrates in the form of including flatbreads and white rice which are lower in fiber. Foods are often fried or cooked in large amounts of oil and in some parts of South Asia, vegetarian diets can often be low in protein content.

Sweets and fried foods are a big part of many religious and cultural traditions. These dietary patterns often lead to high LDL (‘bad cholesterol’), low LDL (‘good cholesterol’), and high triglycerides. They also contribute to insulin resistance, elevated glucose, elevated uric acid, metabolic syndrome, pre-diabetes, and diabetes.

In addition, studies show that while Canadian-born South Asians eat fewer traditional foods, they do tend to drink more alcohol and sugar beverages and eat more fast food than people born in South Asia. Unfortunately, given our genes, these changes in our diet affect us more than most and lead to even more of the metabolic issues identified above.

One study done in Alberta comparing South Asians to the average Canadian found that although 76 percent of the respondents were vegetarians and eating seven servings of fruit and vegetables compared to four servings for the average Canadian - up to one-third of their daily calories were coming from processed foods high in sugar, sodium, and fat. This is compared to 20 percent for the average Canadian [10].

South Asian Psychology

While binge eating and other eating disorders are not well-studied in the Canadian South Asian population, bias against overweight South Asians may be higher, especially within the community. While it is culturally accepted for South Asians to be overweight (especially men) as this is considered a sign of prosperity or even good health, it is not considered acceptable for women and is often stated bluntly to those who have a higher weight. This may lead to a higher internalized bias among people who are overweight - leading them to blame themselves for having no willpower and isolating themselves, leading to higher rates of depression and anxiety.

South Asian Activity

In general, adults are not as often engaged in organized sports as Europeans. Many traditional Indian sports such as cricket are not as popular in Canada. Studies show that a substantial proportion of the population may not be engaged in vigorous physical exercise. For the first generation of immigrants, migration to a new country often leads to long working hours, worsening physical inactivity, and chronic stress, all of which contribute to weight gain. A disproportionate number of South Asians are in sedentary jobs often found in the fields of information technology, business, and even health care. Studies have also found that Canadian-born South Asians have a higher level of screen time as compared to South Asians living in their native countries.

This is all highly concerning because in one study Asian Indian men with an average BMI of 26.1 had only 81.5% of the appendicular skeletal muscle mass of European men with a lower BMI (average of 25.8). Indian Asian women didn’t fare much better - with an average BMI of 26.3, they had a skeletal muscle mass of 84% compared to European women with an average BMI of 24.8 [11]. In general the higher your BMI, the more muscle mass you should have (since your leg muscles hypertrophy in order to carry additional weight). Skeletal muscle mass is healthy and helps to counteract some of the negative effects of visceral abdominal fat. These findings are likely related to the findings listed under the epigenetics section above and provide more evidence of why it is important for South Asians to keep our body weights down and to exercise more given our genetic and epigenetic disadvantages.

Treatment Criteria for Medications and Surgery

Since we have a higher risk of many metabolic diseases at a lower BMI than people of European origin, we should consider active treatment for weight earlier than them. In addition to focusing on nutrition and exercise, we should support them with the three pillars listed in the Obesity Canada guidelines - psychology, medications, and surgery.

We should consider medications at a BMI >25 when we already have another metabolic or mechanical condition (such as fatty liver, high blood pressure, high cholesterol, sleep apnea, insulin or glucose abnormalities, lower back/hip/knee/ankle arthritis). We should also consider medications for anyone with a BMI >27 to prevent the development of any of these abnormalities. When using waist circumferences (WC), we should consider medications with a waist size >100 cm (40 inches) for men and >90 cm (35 inches) for women [8]. You can learn more about weight loss medications here.

We should consider bariatric surgery (in addition to nutrition, exercise, psychology, and medications) for a BMI of >32.5 with any of the weight-related diseases listed above or with a BMI of 37.5 without any of the diseases listed above. This is lower than the recommendations for most people. The current guidelines recommend surgery for people with a BMI of >40 without any weight-related diseases or >35 with any associated weight-related diseases. Unfortunately, it may be difficult to obtain weight loss surgery in Canada due to long weight times. You can learn more about the different types of surgery here.

Links

Here are some links to specific nutrition and exercise advice for South Asians:

Diabetes Canada - 7-Day South Asian Healthy Meal Plan.
https://www.diabetes.ca/nutrition---fitness/meal-planning/7-day-south-asian-healthy-meal-plan

Hamilton Health Sciences “Healthy Lifestyle for South Asians” Handout.
https://www.hamiltonhealthsciences.ca/wp-content/uploads/2019/08/BMISouthAsian-trh.pdf

Heart and Stroke Foundation: Healthy Eating for South Asians.
https://www.heartandstroke.ca/-/media/pdf-files/canada/south-asian-resources/366_southasianheathyeating_single.ashx

Heart UK: South Asian Diets and Cholesterol.
https://www.heartuk.org.uk/healthy-diets/south-asian-diets-and-cholesterol

National Lipid Association: Heart-Healthy Eating South Asian/Indian Style.
https://www.lipid.org/sites/default/files/heart_healthy_eating_south_asian_style.pdf

Sutter Health: A Healthy South Asian Diet.
https://www.sutterhealth.org/health/nutrition/healthy-south-asian-diet

Advocate Health Center: South Asian Nutrition and Heart Health.
https://www.advocatehealth.com/health-services/advocate-heart-institute/programs-and-treatments/preventive-care/south-asian-cardiovascular-center/nutrition-heart-health

Brown Women Health: Healthy Diets for South Asian Women
https://medium.com/brown-women-health/healthy-diets-for-south-asian-women-49e4b675116a

UT Southwestern Medical Center: Cardiometabolic Risk in South Asians
https://utswmed.org/heart/physician-update/cardiometabolic-risk-in-south-asians/

References

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