The importance of fats and healthy fats are often misunderstood in fitness circles when talking about health, weight loss, or muscle gain. Common questions that come up include, what are the good fats to eat, do we need fat in our diet, and does eating fat make me fat?
It’s time to clear a few things up and find out what dietary fats are, which ones are healthy, what fats you should avoid, as well as the best fats for weight loss.
What are fats?
Dietary fats are an essential part of the human diet. You have to eat a certain amount of dietary fat on a daily basis to keep your body running properly. They have many important roles in the body, such as helping to produce powerful hormones like testosterone. They also give cells structure and support, as well as being an important energy source at rest.3
Fats are very energy dense and they contain around 9 calories per gram. This is just over double the amount that protein and carbs have. 3 So, whilst it’s important to get some in the diet, you need to watch that you don’t overeat and push over into an unwanted calorie surplus, which leads to weight gain. Most guidelines agree that 20% to 30% of our daily calories should come from dietary fats. 5 This could, of course, be more if you’re following a high-fat, low-carb diet, but shouldn’t be lower than 20% for extended periods of time.
What does “healthy fats” mean?
Many people have different ideas about what a healthy fat is. There’s actually no clear scientific definition of what a healthy fat is. There are two main groups of fats —unsaturated and saturated (these are broken down further into sub-categories). What causes fat to be saturated or unsaturated is the difference in the carbon bonds. Unsaturated fats have a double bond between some carbon atoms. Saturated fats don’t have this double bond between the carbon atoms, so they end up being packed much closer together than the unsaturated equivalent. 7
Healthy high-fat foods that are good to eat
The majority of fats in your diet should be unsaturated fats. This is broken down into two groups as discussed earlier — monounsaturated and polyunsaturated fats.
Healthy sources of unsaturated fats:
- Almonds, walnuts, pistachios and other nuts
- Nut butters (watch for added sugar)
- Olive oil
- Ground Flaxseed
- Sunflower seeds
- Chia Seeds
Healthy sources of saturated fats:
To be eaten in limited amounts
- Grass fed beef
- Full fat milk
- Full fat yoghurt
Good fats vs bad fats
As a general rule, unsaturated fats are thought to be the healthier type of fat. The recommendation is that around 90% of our daily fats should be from an unsaturated source. Saturated fats have been linked to cholesterol — hence the broad stroke 10% recommendation. 8
Most of the guidelines are centred around cardiovascular disease and heart health. Unsaturated fats tend to be high in HDL (a lipoprotein that carries cholesterol away from the heart) and LDL (a lipoprotein which carries cholesterol to the heart). 4
Unsaturated fats tend to be liquid at room temperature. They’re broken down into two distinct types: monounsaturated fats and polyunsaturated fats.
These tend to be more plant based. Sources include avocados, vegetable oils, nuts, and seeds.. These fats have been linked to improved heart health, lower inflammation, improved weight loss, and improved insulin sensitivity. 9
These are both marine and plant based. PUFA’s have received a lot of media attention as they are high in omega-3. The marine source tends to be absorbed better by our bodies than the plant based version. These fats have been linked to cardiovascular health, brain development in children, low levels of inflammation, and a healthy immune system — just to name a few. 9
These are often mistaken for an unhealthy fat. Saturated fats are generally associated with heart disease as they are high in cholesterol. This has been challenged as science and research develops — especially in the absence of a calorie surplus (when you eat more calories than you burn). 4
Saturated fats tend to be solid at room temperature and are found more in animal products. Saturated fats play a very important role in steroid sex hormone production and brain function. This is because this fat is high in cholesterol, so some is important in the diet. If you’re unsure of how much to get, then stick to the national health guidelines of no more than 10% of saturated fat per day. 4
These are known by a few names. If you see the word hydrogenated or partially hydrogenated, then these are trans fats. Trans fats are man-made fats. They’re unsaturated fats that go through a process to make them solid at room temperature. There’s no healthy amount of trans fats you should have in your diet. There are strong links that if there is just a small percent of trans fats in the daily diet, the risk of heart disease goes up exponentially. 1
There are zero health benefits associated with trans fats and the laws in most countries have made it so that trans fats have to be labelled separately. They’re often found in packaged pastries or cookies, as this fat extends the shelf life of the product. 1
Unsaturated fats have proven health benefits and are considered the healthiest amongst the fats. Saturated fats have some essential properties but should be limited on a daily basis. Trans fats have no place in the diet and should be avoided at all costs, even a small amount can be incredibly unhealthy. 1
Are there good fats for weight loss?
This is a double-edged sword. Fats have 9 calories per gram, which is just over double the amount that protein and carbs have.3 Fats are very calorie dense and, for some, easy to overeat. If you want to lose weight, you need to be in a calorie deficit (consuming fewer calories than your body uses as fuel). By consuming too many fats you, can put yourself in a calorie surplus.
There’s no special fat that will make you lose weight. However, there are some fats that might help the body breakdown stored fat to be used as fuel. In combination with a calorie deficit, this might make weight loss a little more efficient.
- Omega-3 fish oil: There’s some research showing that, in overweight populations, eating a diet high in omega-3 might slightly aid weight loss. The caveat is that this needs to be combined with diet and exercise. The results were still modest at best, but there might be a small benefit to weight loss. In addition, omega-3 is very healthy, with plenty of additional benefits, so it could be a good idea to have a diet rich in these.10
- MCT oil: This is a medium chain triacylglycerol that is metabolised very differently compared to other fats. MCT is broken down and metabolised by the liver and isn’t readily stored like other fats. MCT, used in combination with a calorie deficit and exercise, could be a useful strategy for weight loss. Similar to omega-3, the results are modest, but it could help make a small difference to weight loss. 6
Take home message
Fats are an essential part of the diet and not all are unhealthy, in fact some may even help with weight loss. Most guidelines recommend a minimum daily allowance of 20% to 30% of calories that need to come from fat. Fat is extremely energy dense at 9 calories per gram. If health and weight loss are on the agenda, it’s important to track diligently and not overeat fats and calories.