Do 'good genes' matter when it comes to losing weight?
A study at the Stanford University School of Medicine suggests that genetic patterns have very little bearing on your ability to lose or put on weight
If you have ever blamed your genetic make-up for stopping you from losing weight or, as is more likely, envied a svelte friend their “good genes”, your chances of being right are, er, slim. Researchers from Stanford University in the United States conducted a year-long study that indicates that the amount and quality of food that a person consumes is responsible for weight loss – completely irrespective of his or her genetics.
The experiment randomly assigned 609 obese adults to reduce their intake of either carbohydrates or fats. The two groups were asked to reduce their daily calories by 500, avoid processed and sugary foods, and focus on mindful eating. The researchers also looked to see whether participants had a particular genotype within the PPARG, ADRB2 and FABP2 gene combinations. These three common DNA codes were previously thought to react differently to low-fat and low-carb diets. However, the Stanford study deliberately allocated the two meal plans to a mixed sample.
After 12 months, the differ-ence between the average amount of weight lost by the members of each group was a mere 0.4 kilograms, irrespective of their genotype, insulin levels or diet type, suggesting that when it comes to weight-loss success, cutting out carbs or fats holds equal sway. This suggests that DNA-based diets, which have become increasingly popular in recent years, are ineffectual for those with the PPARG, ADRB2 and FABP2 gene combinations, which covers the majority of people. “Nothing has proved until now that a person should follow a diet based on their DNA. Our genes are only one factor that may contribute to obesity, but this is not a determinant factor,” agrees May Al Joudeh, a dietician at Medeor 24x7 International Hospital Al Ain.
“To be sure, this does not include certain conditions such as coeliac disease, or food allergies and intolerances. What this study shows is that a person may have a family history of obesity, diabetes or even an irregular thyroid, but if they make healthier food choices and practise better lifestyle habits, they will be able to control their weight,” she explains.
The findings, which were published in the Journal of the American Medical Association last month, also established, perhaps unsurprisingly, that the individuals who had consumed the most vegetables reported the best results.
“You may have heard many times that not all carbs are bad for you and not all fats are bad either, but how many of us actually know the difference, the dos and don’ts?” asks nutritionist Sadaf Gulzar, of UAE-based healthy meal-delivery service Love Food, Love Life. “For example, did you know that cooking your food in butter is better than any number of vegetable oils? Or that some complex carbs can actually reduce the risk of type 2 diabetes [even if this is believed to be hereditary]?”
It seems a refresher course on carbohydrates and fats might be in order. The former is the body’s main source of energy; it is made up of sugar, starch and fibre, and is either simple or complex. “Simple carbs include the glucose found in honey, fructose in fruits, sucrose in table sugar and lactose in milk,” explains Gulzar. “They enter our blood stream immediately and are a fast source of energy.” Complex carbs contain longer chains of sugars, which the body needs to break down in order to use as fuel.
“When we refer to good carbs, it’s mostly those complex carbs that are as close to their natural state as possible, or unrefined in other words. Refined carbs, such as sodas and candy, are considered bad because they are made up primarily of sugar, or because the sources they come from have been processed to an extent that strips away all their nutrients,” she says. “Good carbs, such as wholegrains, vegetables and fruits, are plant-based foods that deliver fibre, vitamins and phytochemicals. They keep you full for a longer time, are digested slowly and keep sugar levels stable, so they also lower cholesterol levels and reduce the risk of type 2 diabetes.”
Maligned as they have been in the past, fats, too, are essential for optimal functioning. They help build cell membranes to protect the vital organs, and are needed for blood clotting, muscle movement and to curb inflammation. There are two types of fats: saturated and unsaturated, which are further divided into monounsaturated and polyunsaturated.
“Saturated fats mostly come from animal fats [butter, ghee] and tropical oils [coconut]. Monounsaturated fats come from nuts, avocados and olive oil. Polyunsaturated fats include either omega-3, from fish and walnuts, or omega-6, from canola oil, sunflower oil and corn oil,” says Gulzar.
After decades of assuming that saturated fats increase your bad cholesterol levels (LDL), scientists discovered there is not enough to link them to heart disease or stroke. “If anything, saturated fats raise your HDL [good cholesterol]. They are excellent for cooking as they are highly resistant to the damage caused by heat. The truly harmful variant is artificial trans fats, which involves exposing polyunsaturated fats such as vegetable oil, to chemical processes that involve high heat, hydrogen gas and metal catalysts, which has shown to increase risk of insulin resistance and heart disease. Plus, processed vegetable oils are high in omega-6 fatty acids, overconsumption of which causes inflammation,” she says.
In a word, vegetables, at least according to the Stanford study. “Any healthy diet will emphasise increasing plant-food consumption – vegetables, fruits, whole grains, legumes and nuts. But vegetables are especially important because they are usually lacking in the average individual’s diet, so changing that will display visible health benefits,” notes Al Joudeh.
“Vegetables are important for weight loss in particular because they contain fibre, which helps regulate the sugar digestion and absorption in the intestines, and curb food cravings, reduce the absorption of cholesterol and make you feel fuller for a longer time. Vegetables also naturally contain the minerals and vitamins the body needs to increase and regulate the metabolism, which burns energy, and aides weight loss.”
While more research is needed on other types of genotype signatures and patterns not explored by the study, its findings definitively prove the efficacy of any high-quality, low-quantity food regimen for weight loss. Bad genes can no longer be used as an excuse.
Updated: March 11, 2018 09:44 AM