Is low-fat really good for you? What exactly are trans fats, and why do so many products feature them on the ingredients list? Find out more here.
Since the 1980s, we’ve been recommended to steer clear of fats as everyone in the world thought that eating lots of fat, makes you, well, fat. High fat diets were thought to lead to obesity, heart disease, and cancer. But does that theory still hold water?
Going fat-free won’t stop you from gaining weight
Many scientists are now questioning the overly simple message about reducing fat – especially when emerging research showing us that there are different types of fat contributing to our bodies differently.
Even the World Cancer Research Fund (WCRF) no longer includes a recommendation on fat reduction, in contrast to previous reports. Specifically, the WCRF and the American Institute for Cancer Research report on “Food, Nutrition, Physical Activity and the Prevention of Cancer” (2007) reviewed all of the science on dietary fats and oils and cancer risk.
A diet high in fat does not lead to cancer by itself
The report concluded that “…there is only limited evidence suggesting that diets relatively high in fats and oils (in total or any type) are in themselves a cause of cancer. These findings contrast with those of earlier reports which concluded from evidence then available that diets high in fats and oils might be a substantial cause of some cancers.”
It’s the calories that count
Body weight is determined by a complex interaction between genetic, metabolic, behavioural, environmental and cultural influences.
Your body weight increases when you take in more calories than you burn. Fats feed you with twice the calories of proteins and carbs, and will cause weight gain if the excess calories are not balanced by physical activity.
However, it’s not fat alone that causes an excessive intake of calories. Calories, regardless of its source can lead to weight gain if taken too much.
Are you looking at the wrong nutritional values?
In Asia, we are obsessed with fat.
A recent study on food labelling undertaken by AFIC (2007) found that “fat content” was the most commonly searched for information on nutrition labels on foods in Shanghai. In Bangkok, fat content was the fourth most commonly sought piece of information.
In both cities, consumers were more likely to search for fat levels than for calorie levels. The study also found high levels of confusion about the role of fats in the diets. Significant numbers of consumers associated fat only with calorie levels and many believed that the energy or calorie figure on food labels represented calories from fat alone.
Interestingly, consumers in both Bangkok and Shanghai did not appear to understand the concept of energy balance or the fact that energy/calories are derived from carbohydrates, proteins and fats – they believe (at least in a significant percentage of respondents in the study) that calories are just derived from fats.
In both cities, people tended to rate the relative healthiness of meals based on the fat content. Those who claimed to read the nutrition labels supplied in the AFIC study tended to use the fat levels as the main criteria to assess the meal’s healthiness or otherwise. In Bangkok, people tended to use the fat levels to determine whether the meal would make them “put on weight”.
There are different kinds of fats, and some are good for you
While most of us lump fat together under one big umbrella, there are actually multiple different types of fat. Some which are great for your body, and some which are just hanging around to wreak havoc.
The bad guys – trans fats and saturated fats
Excess intake of saturated and trans fats can increase blood cholesterol – a risk factor in the development of coronary heart disease (CHD). Trans fats can also lower high density lipoprotein (the good cholesterol) levels.
The good guys – monounsaturated fats and polyunsaturated fats
Reduce your risk of heart disease by replacing these bad fats with good fats like monounsaturated, and polyunsaturated fats.
Eat the right fats
Back then, low fat diets were your go-to fix for preventing heart disease. However, new research suggests that higher fat diets with better palatability may provide better heart health benefits – provided the right type of fat is eaten.
A study comparing low fat (12% total fat) weight loss diets to those with a level of 35% monounsaturated fat – but with equivalent calories – reported that the diet high in monounsaturated fats lowered LDL cholesterol and oxidative susceptibility, thereby lowering the risk of coronary heart disease.
Mediterranean populations eating traditional diets, with high intakes of monounsaturated fats, also appear to enjoy cardio-protective effects.
What are trans fatty acids (or trans fats)?
Hydrogenated oil doesn’t go bad as quickly and has a longer shelf life. They also make margarines more spreadable, and pastries like roti canai or prata flakier. This is why the food industry is in love with the hydrogenation process.
Your body however, is not a big fan. Through the process of hydrogenation, the healthy fats within the oil are converted into another type of fatty acid, known as trans fatty acids (TFAs).
The US National Academy of Sciences has concluded that TFAs raise your low-density lipoprotein (LDL – the bad cholesterol) levels, while lowering your HDL levels.
These findings have led to many governments requiring trans fatty acids to be labelled on foods. Norway has gone a step further and limited the amount of TFAs in the food supply by setting strict limits on the levels of TFAs in foods. Oils and fats with more than 2% TFA content are banned from sale in Norway. If a country is banning trans fats, you should probably cut your intake of trans fatty acids as low as possible.
Your keyword = balance
Eating too many fats of any kind can be harmful to health but excluding fats can cause a dietary imbalance.
The body requires about 25g of fat a day to enable it to absorb fat soluble vitamins and beta carotene. Fats are also vital for the provision of essential fatty acids (omega 3 and omega 6 fatty acids) which the body cannot produce itself.
Your action plan for a balanced diet:
- Replace trans (check food labels for TFA content) and saturated fats (animal fats such as butter, the fat on meat) with monounsaturated (olive, canola, avocadoes, nuts) and polyunsaturated (safflower, sunflower) fats
- Try to eat oily fish (such as salmon, tuna, sardines and mackerel) at least twice a week. These fish are excellent sources of omega-3 fatty acids
- Choose low-fat dairy products and lean cuts of meat trimmed of fat. Remove the skin from poultry
- Eat natural sources of fat such as nuts, seeds, grains, avocadoes and fatty fish to obtain extra nutrients and phytochemicals.
What are your favourite foods that are high in monounsaturated and polyunsaturated fats? Share with us in the comments below or on our Facebook page!