For centuries, the human body has relied on fat for fuel, underscoring the importance of fat in your diet. It is estimated that humans can store enough fat in their bodies to walk almost 10,000 kilometers, although we do not recommend attempting this. As part of our evolution, it was crucial for the human body to be able to store fat because food supplies were extremely limited compared to today, and food security was virtually nonexistent.
Another factor of modern-day life that has changed over the last hundred years is the amount of physical activity we engage in day-to-day. The types of exercises we have neglected, such as walking to work or taking the stairs, have been replaced by modern conveniences like driving and escalators. This shift has resulted in increased fat intake and lower energy expenditure, leading to the generalisation that the population carries more excess fat than before.
I would argue that, right now, you are predominantly metabolising fat while reading this blog post—assuming you haven't recently consumed carbohydrates. This is because activities of very low intensity, such as sitting, walking, reading, or watching television, all rely on fat as a fuel source. It's only when we increase our exercise intensity, like transitioning from a walk to a more intense run, that carbohydrates become the primary fuel source. This is why you often hear about people engaging in low-intensity, fasted exercise to metabolize fats.
So, why is fat important, all things considered? To answer this question, we must understand the three different types of fat. First, there are unsaturated fats (e.g., nuts, seeds, and fish oils), which should be the primary fat source in our diets. These fats provide the body with essential nutrients and can reduce inflammation. For instance, Omega-3, found in oily fish like salmon, also enhances muscle function. The second type of fats is saturated fats, which are abundant in dairy and meat products. While they remain important in the diet, excessive consumption of these products can have implications for cholesterol levels and unwanted weight gain. The third aspect is trans fats, which are common in processed or highly manufactured foods—this is a type of fat we should aim to limit in our diets.
All fats are unique compared to the other two macronutrients, carbohydrates and proteins, in that one gram of fat provides 9 calories, whereas carbohydrate and protein each provide only 4 calories. Therefore, it's crucial to understand that if we typically consume a diet high in fat, we are also consuming a diet that is higher in calories. This can be detrimental to our training goals if we are seeking to manipulate our body composition. When considering our training goals, it is essential to adhere to nutritional guidelines. Nutritional recommendations for fats suggest that we do not regularly consume more than 1 gram of fat per day for every kilogram of our body mass. In certain sports, where weight reduction is a goal, such as boxing or sports where power-to-weight ratio, like road cycling, is crucial, this number can be reduced even further.
To sum it all up, if you weigh 70 kilograms, for example, you should aim to consume 70 grams of fat each day, primarily from unsaturated fat sources, which also provide numerous other benefits, such as a richer profile of micronutrients and essential fatty acids like omega-3. That being said, if you indulge in an extra burger and sausage at a summer BBQ, it's not something to beat yourself up over. However, if your goal is to reduce body fat, consider swapping deep-fried cod and chips for a large fillet of oily fish like sea bass. You can also add salad with olive oil and roasted pine nuts for multiple sources of healthy fats.