A few facts about fat for a vegan diet

Fat! Enemy of dieters; curse of the worldwide obesity epidemic. Avoid it all costs. Or, maybe not? Not all fats are quite the villains they are portrayed to be. In this post, I’ll look at the various types of fats and consider what vegans need to do to achieve the best intake of dietary fat.

Saturated fat

Fats and oils are comprised of chains of fatty acids and glycerol. These fatty acids are made up of carbon atoms to which hydrogen and oxygen atoms are attached. The type of fat depends on the number of hydrogen atoms that the carbon atoms in the chain can hold. If the fatty acid chain has all the hydrogen atoms that it can hold it is said to be saturated. These types of fat are found in large quantities in meat, fish and dairy products. They can also be created by the hydrogenation process which is used to turn liquid oils into solid fats. Plant foods contain much lower levels of saturated fat, except coconut oil and palm oil. (Coconut oil actually has more saturated fat than butter!) A  high intake of saturated fat has been linked to heart disease, high cholesterol and diabetes, hence the recommendation to minimise saturated fat intake.

Monounsaturated fats

Following the science outlined above, monounsaturated fatty acids have one hydrogen atom missing and replaced by a double bond between the carbon atoms. This type of fat is usually liquid at room temperature but thickens in cold. Monounsaturated fats include olives, olive oil, avocados and some nuts. These type of fats are either beneficial for health, or have no effect. They are generally considered to be the good guys.

Polyunsaturated fats

As the prefix ‘poly’ (many) implies, these types of fatty acid have more than one hydrogen atom missing from the carbon chain. Like their mono cousins, polyunsaturated fats generally have beneficial effects on health and are recommended as replacements for saturated fats and other baddies. Vegan sources of polyunsaturated fats are vegetable oils, nuts, seeds, grains, legumes and some vegetable plant foods.

Trans fats – the real baddies

Trans fats, like saturated fats, have received a bad press for their negative effects on cholesterol levels. Some meat and dairy products naturally contain trans fats, but the biggest culprit is the hydrogenation or partial hydrogenation process. This is a manufacturing process involving adding hydrogen to liquid fats (oil) to convert it into a solid fat, such as making margarine, and to improve the shelf life and taste of processed foods. It was here that margarine got a bad name that’s not always justified. Vegans do need to watch out – if you use non-dairy spreads, for example, check the label carefully. My favourite Fruit d’or spread states that it contains no hydrogenated fats or trans fats.

Essential fatty acids

There’s one more term the vegans need to be aware of in relation to fat facts. Two types of fatty acid cannot be made by the body and are therefore known as ‘essential fatty acids’ or EFAs. These are linoleic acid (LA), which is in the Omega 6 family, and alpha-linolenic acid (ALA), which is in the Omega 3 family. It’s important to have a balance between these two groups. On a plant-based diet, vegans are likely to have a fairly high intake of omega 6. It’s found in foods like soybeans, sunflower and pumpkin seeds, amongst others. There has been a great deal of research around the ideal ratio of omega 6 to omega 3, but no general consensus between the experts. For vegans, “the evidence to date suggests a range of 2:1 to 4:1” (Davies & Melina, 2014, p. 122). Ensuring an adequate omega 3 intake can be a simple matter of adding two tablespoons of ground flaxseeds or chia seeds to your morning muesli or snacking on a handful of walnuts.

Fat targets

The nature of the vegan diet tends make it healthier in terms of low levels of saturated fats and trans fats which are derived from animal products. As mentioned last week, the average target for dietary fat is to consume 20 to 35% of calories from fat. At nine calories per gram, one gram of fat has just over twice as many calories as a gram of protein or carbohydrate. Hence, on an average 2000-calorie per day diet, vegans should be aiming for around 560 calories of fat or 62g. Most of this should be in the form of mono- or polyunsaturated fats, avoiding high intakes of unhealthy saturated fat and trans fats.