Does eating fat cause you to gain body fat?
Does eating fat cause you to gain body fat?
When it comes to nutrition and weight loss, dietary fat often gets a bad rap. For years, we’ve been told to avoid fat if we want to lose weight or maintain a healthy lifestyle. This has led to low-fat diets dominating the weight-loss industry for decades (diets such as the “pritikin diet” or the “ornish diet”. Ps, I had to Google these, I hadn’t heard of them before in Australia . But is eating fat really the culprit behind weight gain? Let’s have a little looksie.
What is Fat, and Where Is It Found?
Fat is one of the three macronutrients (well, four if you count alcohol as a macronutrient) that provide energy for the body. Alongside protein and carbohydrates, fat as a macronutrient plays an essential role in maintaining overall health and supporting bodily functions. Some of the roles of fat include:
Energy Storage: Fat is a concentrated energy source, providing 9 calories per gram, compared to 4 calories per gram for protein and carbohydrates. While this may sound like a ‘bad’ thing to be storing energy, it can be very helpful in situations that may require us to require stored energy (such as long periods without food).
Nutrient Absorption: Fat helps the body absorb fat-soluble vitamins like A, D, E, and K.
Cellular Health: Fats are a crucial component of cell membranes and are necessary for hormone production and brain health.
Satiety and Flavor: Fat contributes to the feeling of fullness after a meal and enhances the flavour and texture of foods. Think of foods like olive oil, cheese, smoked salmon, olives, mm.
You can find dietary fat in a variety of foods, such as:
Animal-based sources: Butter, cheese, eggs, fatty cuts of meat, fish like salmon and mackerel.
Plant-based sources: Nuts, seeds, avocados, olives, and plant-based oils (olive oil, coconut oil).
Processed foods: Many packaged snacks, fried foods, and baked goods contain added fats, often in the form of ‘less healthy’ fats such as trans fats.
What Does It Take to Gain Weight?
Weight gain is determined by energy balance, which refers to the relationship between the calories you consume (caloric intake) and the calories your body burns (caloric expenditure). If you consume more calories than you burn, you’re in a calorie surplus, which leads to weight gain over time. Conversely, if you consume fewer calories than your body needs, you’re in a calorie deficit, and you’ll lose weight.
Several factors influence whether you’re in a calorie surplus or deficit:
- Caloric Intake: The total number of calories consumed from all sources—protein, carbs, fat, and even alcohol.
- Energy Expenditure: The calories your body uses daily, including:
- Basal Metabolic Rate (BMR): The energy your body needs to perform basic functions like breathing, circulation, and cell repair.
- Physical Activity: The energy burned during exercise and everyday movements like walking or cleaning.
- Thermic Effect of Food (TEF): The small number of calories burned digesting and metabolising food.
- Lifestyle Factors: Hormonal health, sleep quality, stress levels, and even genetics can influence how efficiently your body burns calories.
Gaining weight is not about one specific macronutrient. Whether the extra calories come from fat, protein, or carbs, if you’re in a calorie surplus, your body has the ability to store the excess energy as fat (or muscle, if we are being more strategic with our nutrition).
The Truth About Fat and Weight Gain
The myth that “eating fat makes you fat” likely stems from fat’s calorie density. Since fat provides more than twice the calories per gram compared to protein or carbohydrates, it’s easier to over consume calories when eating fat-rich foods. However, fat itself is not inherently fattening.
What actually matters is the overall calorie balance, not the type of macronutrient consumed. Let’s break this down further:
Calorie Surplus:
If you eat more calories than your body burns, you’ll gain weight, whether those calories come from fat, protein, carbs (or alcohol).
Calorie Deficit:
To lose weight, you need to consume fewer calories than your body burns, regardless of how much fat you eat.
PS: If you want to learn more about energy balance, Precicion Nutrition have a detailed blog on this, here.
Does Eating Fat Specifically Lead to Weight Gain?
Not specifically, no. All macronutrients—fat, protein, carbohydrates (and alcohol)—can contribute to weight gain when consumed in excess. Here are some key points:
Carbohydrates and Protein: While they provide fewer calories per gram, overeating them can still lead to fat storage if total calorie intake exceeds expenditure.
Fat’s Role: Fat’s calorie density means that it’s easier to consume more calories when eating high-fat foods, especially if portion sizes aren’t controlled. For example, a handful of nuts can contain 150–200 calories, which can add up quickly if you’re not mindful. That being said, fat as a macronutrient can be more satiating (and make you feel fuller for longer), so, we don’t want to just cut these foods out altogether.
This doesn’t mean you should fear fat. In fact, fat is essential for health and can even support weight loss when included in a balanced diet.
Why Fat is Just One Energy Source
It’s important to view fat in the context of your overall diet. Fat is one energy source among many, and its impact on your weight depends on how it fits into your total calorie intake.
- Fat and Satiety: Fat is more slowly digested than carbohydrates, which can help keep you fuller for longer. Including healthy fats in your diet may help you stick to a calorie deficit without feeling deprived.
- Quality Matters: Not all fats are created equal. Unsaturated fats, found in foods like avocados, olive oil, and fatty fish, have numerous health benefits, while trans fats (found in processed foods) should be reduced, if possible.
- Balance is Key: A balanced diet includes all macronutrients—fat, protein, and carbs—in proportions that align with your energy needs and goals. Including fats is important for your overall health (as we mentioned), and removing it because you think eating fat will make you fat, is not true.
The Takeaway
The idea that eating fat makes you fat is a myth. Weight gain occurs when you consume more calories than your body burns, regardless of whether those calories come from fat, protein, or carbohydrates. Instead of fearing fat, focus on:
Portion Control: Fat-rich foods are calorie-dense, so be mindful of serving sizes, especially with items like oils, nuts, and seeds. We still want to include them, but if you have a low calorie budget (that is, the amount of food you need to be in a calorie deficit), you may want to be more mindful of these foods).
Choosing Healthy Fats: Prioritise unsaturated fats from foods like avocados, nuts, seeds, and fatty fish to support heart health and overall well-being.
Maintaining Energy Balance: Your total calorie intake matters more than any one macronutrient.
By understanding the role of fat in your diet and focusing on balance, you can make informed choices that support your health and weight-loss goals without unnecessary restrictions. If you have found this article interesting, I’d love to hear about it. Feel free to reach out to me on @ccdietitian.
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