During a cut, you should aim for 20 to 35 percent of your total daily calories from fat, with most people landing best around 20 to 25 percent when actively losing weight. In grams, that works out to roughly 0.5 to 1.0 grams of fat per kilogram of body weight per day. Going below 15 to 20 percent of total calories from fat is where problems start, including hormonal disruption and poor vitamin absorption.
The Recommended Range in Grams
Percentages are useful, but grams are what you actually track. The International Society of Sports Nutrition recommends 0.5 to 1.0 grams of fat per kilogram of body weight per day during an active cut. For someone weighing 180 pounds (about 82 kg), that’s roughly 40 to 82 grams of fat daily. Where you land in that range depends on how aggressive your calorie deficit is and how many carbs you need to fuel your training.
A practical way to set this up: calculate your protein first (the non-negotiable macro during a cut), set fat at around 0.7 to 1.0 g/kg, then fill the remaining calories with carbohydrates. If your deficit is steep and calories are tight, fat can drop toward 0.5 g/kg temporarily, but this should be a short-term strategy rather than a months-long default.
Why You Shouldn’t Go Too Low
Fat is a common target when you’re trying to cut calories because it’s the most calorie-dense macronutrient at 9 calories per gram, more than double the 4 calories in a gram of protein or carbs. But cutting fat too aggressively creates real physiological consequences that work against your goals.
Low-fat diets significantly reduce total, free, and urinary testosterone levels. For men, this matters directly for muscle retention and recovery during a deficit. Men of European ancestry appear to experience an even greater decrease in testosterone on low-fat diets. Women also see hormonal effects: higher fat intake, particularly from polyunsaturated sources, is associated with increased total and free testosterone, which plays a role in maintaining lean mass and supporting ovulation.
Fat intake below 10 percent of total calories compromises your ability to absorb fat-soluble vitamins, particularly vitamins A and E. Since a cut already limits overall food variety and volume, restricting the one macronutrient responsible for transporting key vitamins is a poor trade-off. The floor for safe fat intake sits at 15 to 20 percent of total calories for most people.
Fat vs. Carbs: What to Cut First
When you’re in a deficit, the calories have to come from somewhere. The choice usually comes down to pulling from fat or carbohydrates, and the answer depends largely on your training style. If you lift heavy or do high-intensity work, carbohydrates directly fuel those sessions. Dropping carbs too low can tank workout performance, which indirectly costs you muscle. In that case, keeping fat at the lower end of the range (0.5 to 0.7 g/kg) while preserving more carbs makes sense.
Research comparing very-low-carb and low-fat diets during a deficit shows mixed results for lean mass preservation. One study found that both very-low-carb and very-low-fat diets led to more lean mass loss than a moderate approach with higher unsaturated fat intake. The takeaway: extremes in either direction tend to be worse for body composition than a balanced split. A moderate fat intake of around 20 to 30 percent of calories, paired with adequate protein and enough carbs to support training, is the most reliable approach for preserving muscle during a cut.
There’s also a notable sex difference. Men tend to lose more weight on low-carb, higher-fat diets, while women achieve similar results regardless of whether they follow a low-fat or low-carb approach. Women also tend to find low-fat diets easier to stick with long term. Adherence matters more than the exact macro split, so choose the approach you can sustain for the full length of your cut.
Which Fats to Prioritize
When your total fat budget is limited, the type of fat you eat matters more than usual. Omega-3 polyunsaturated fatty acids deserve priority. In a 12-week study of overweight individuals on a calorie-restricted diet, those supplementing with roughly 1,000 mg of omega-3s daily (a mix of EPA and DHA) lost significantly more abdominal fat than the group dieting without supplementation. Omega-3s also support recovery and help manage inflammation, both of which are elevated during prolonged dieting.
Beyond omega-3s, focus on fat sources that pull double duty by also providing satiety. Proteins and fats are processed slower than carbohydrates, which means they keep you feeling full longer. When calories are low, this matters enormously for day-to-day compliance. A small handful of nuts, a few eggs, half an avocado, or a serving of salmon can make the difference between feeling satisfied and raiding the pantry at 10 p.m. These whole-food fat sources also come packaged with micronutrients you’d miss out on if you spent your fat budget on cooking oils alone.
A reasonable daily fat lineup during a cut might look like: eggs at breakfast, a thumb-sized portion of nuts as a snack, olive oil on a salad, and fatty fish at one meal. That covers your omega-3s, delivers enough total fat to support hormone production and vitamin absorption, and keeps hunger manageable without eating too far into your calorie budget.
Adjusting Fat Intake as Your Cut Progresses
Most cuts last 8 to 16 weeks, and your fat intake doesn’t need to stay fixed the entire time. Early in a cut, when your deficit is moderate and calories are still relatively high, keeping fat at 25 to 30 percent of total calories is comfortable and sustainable. As you get leaner and need to tighten the deficit further, fat can drop toward the 20 percent mark or closer to 0.5 g/kg.
Watch for signs that fat has dropped too low. Persistent fatigue unrelated to training, dry skin, constant hunger that protein and fiber don’t fix, and for women, changes in menstrual regularity are all signals to add fat back in. These symptoms typically appear when intake stays below 15 percent of total calories for more than a few weeks. If you hit that point, it’s better to slow the rate of weight loss slightly than to maintain an unsustainably low fat intake that disrupts your hormones and undermines the cut itself.