Overview
Athletes often track protein and carbohydrates closely, yet fat tends to get less airtime. Still, dietary fat matters for performance and health. The goal is not to chase an extreme, but to find an intake that supports hormones, nutrient absorption, recovery, and training output. At the same time, pushing fat too low or too high can create trade-offs, especially when total calories and other macros need to fit in the same day.
Why Athletes Need Adequate Dietary Fat
Dietary fat plays a key role in hormone health. For women, very low fat intake can reduce oestrogen and progesterone, and it can also affect testosterone. When fat intake drops too low, menstrual cycle disruption becomes more likely. However, it’s worth remembering that low fat intake often shows up alongside low total energy intake, which can make cause and effect harder to untangle.
Men can also run into problems when fat intake dips too low. In particular, low fat intake can reduce testosterone, and that’s rarely a desirable outcome for athletes.
Fat also supports the absorption of fat-soluble vitamins. Vitamins A, D, E and K contribute to immune function, bone health, and antioxidant defence. On top of that, dietary fat supports cell membrane health and organ health, while also helping with appetite management and satiety.
When you look at fat through the lens of vitamin absorption, a relatively small intake may be enough to support absorption. Still, it’s difficult to pin down a hard cutoff, because absorption can scale with intake and context.
Downsides Of Going Too Low
When fat intake runs too low, hormone disruption becomes a real risk. For women, that can mean reduced oestrogen and progesterone, as well as a higher chance of menstrual cycle disruption. For men, very low fat intake can reduce testosterone.
At the same time, low fat intake and low total energy intake often travel together. Because of that, it helps to interpret low-fat outcomes alongside overall calorie intake, not in isolation.
Downsides Of Going Too High
High fat intake can cause problems at the other end too. Firstly, it can make it easier to overshoot total calories. Even if calories stay appropriate, a higher proportion of calories from fat can crowd out other macronutrients.
When fat displaces protein, muscle growth and recovery can take a hit. Likewise, when fat displaces carbohydrates, athletes may miss out on the performance benefits of carbs and glycogen.
Fat intake can also influence blood lipid profiles. This becomes more relevant when a large proportion of fat intake comes from more saturated fats.
Sweet Spot And Practical Recommendations
A useful starting range sits around 20 to 35% of total calories from fat. This range generally supports energy needs, hormones, and nutrient absorption, while still leaving room for adequate protein and carbohydrate intake.
However, percentages don’t always hold up across different calorie intakes. For example, an athlete might run a higher-calorie surplus phase and then move into a lower-calorie deficit phase. If the same fat percentage stays in place, fat intake could end up too low during the deficit, or higher than necessary in other phases. Larger deficits can skew this further, because protein often stays high, and carbohydrates typically make up most of what remains once fats stay adequate.
A bodyweight-based range can add another layer of practicality: around 0.5 to 1 gram of fat per kilogram of bodyweight. In many cases, there’s no strong need to push up to 1 g/kg unless personal preference or logistics make it easier to hit calorie targets. Beyond a certain point, adding more fat doesn’t seem to meaningfully shift performance outcomes, even if testosterone nudges slightly.
The lower end of that range can still cause issues for smaller athletes. For example, if someone sits around 50 to 60 kg, the very bottom end can land too low in absolute grams. In that scenario, pushing fat higher makes more sense than forcing an overly low target.
How To Set Your Own Targets
How detailed you get depends on how much you care about precision. If you want a simple approach, start with a rough calorie target. You can use a calculator, or you can trial an intake for a period and observe what happens.
From there, set protein around 1.6 to 2.2 g/kg. Next, choose a fat range around 0.5 to 1 g/kg. Then, fill the remaining calories with carbohydrates.
After that, adjust based on what happens in practice. If carbohydrates end up extremely low, moving fat toward the lower end can free up room for more carbs. On the other hand, if carbohydrates land very high, nudging fat up slightly can make the daily intake easier to achieve.
Low Carb Note For Athletes
Low carb approaches come up often, yet research in athletes generally does not show low carb outperforming more carb-inclusive approaches. That doesn’t mean low carb always leads to noticeably worse performance. In some contexts, it may perform similarly, especially as intensity drops.
Low carb also appears more common in ultra-endurance settings, where the work tends to be lower intensity. Still, if someone chooses to go low carb, the fat targets need to shift. In that case, fat intake might rise to around 1.5 to 2 g/kg, and because fat is calorie dense, the total grams often don’t need to climb dramatically.
Key Takeaways
- Athletes need dietary fat for hormone support, vitamin absorption, and overall health.
- Going too low can reduce key hormones and may disrupt the menstrual cycle in women.
- Going too high can crowd out protein and carbohydrates, and it may affect blood lipid profiles, especially with higher saturated fat intake.
- A general fat target sits around 20 to 35% of total calories, although needs shift with goals and total intake.
- A practical bodyweight range sits around 0.5 to 1 g/kg for many athletes, with adjustments based on size, goals, and how carbs land.
- Keeping carbohydrates in tends to make sense, because low carb rarely outperforms for athletes in research