Dietary Fats and Hormone Production: How Low Can Fat Go on a Cut? (0.6-0.8 g/kg)

If you are asking about the minimum fat intake for lifters and testosterone, the practical answer is about 0.6-0.8 g of fat per kg of body weight a day, or 15-30% of your calories. Go much lower for weeks and you risk missing essential fats and fat-soluble vitamins, and you may blunt your hormones. The research on that last part is more mixed than gym lore suggests, and we will lay out both sides below.

This article is part of our complete guide to carbs, fats, fibre and hydration. Here we zoom in on one common mistake: dropping fat to nearly zero on a cut, then wondering why libido, mood and training fell off a cliff.

Why does your body need dietary fat at all?

Fat is not just stored energy. Three jobs matter for lifters.

First, essential fatty acids. Your body cannot make certain fats, so they have to come from food. The ACSM position stand says fat intake should be enough to provide essential fatty acids and fat-soluble vitamins, and to contribute energy for weight maintenance (Rodriguez et al., 2009).

Second, vitamin absorption. Vitamins A, D, E and K travel with dietary fat. Eat almost none and you absorb less of them.

Third, hormone building blocks. Steroid hormones, including testosterone, oestrogen and progesterone, are built from cholesterol. Your liver makes plenty of cholesterol on its own, so you do not need to eat huge amounts of it. The bigger hormonal risk is being chronically underfed overall, which we cover below.

Does low fat intake lower testosterone? What the studies show

This is where the internet gets overconfident, so let us be careful. There are two meta-analyses, and they do not fully agree.

A 2021 systematic review and meta-analysis pooled 6 intervention studies with 206 men comparing low-fat and high-fat diets. Low-fat diets were linked to significantly lower total testosterone (standardised mean difference -0.38), free testosterone (-0.37), urinary testosterone and DHT. There were no significant differences in luteinising hormone or SHBG. The authors concluded that low-fat diets appear to decrease testosterone, but that more randomized trials are needed (Whittaker et al., 2021). A later erratum was published for this paper, so check the journal page if you want the final figures.

A 2025 meta-analysis took a wider net: 11 randomized trials with 888 adults, comparing diets with 30% or less of energy from fat against higher-fat diets. It found no significant differences in testosterone, estradiol, SHBG, progesterone and other sex hormones. The authors flagged the small number of studies and low certainty of evidence (Soltani et al., 2025).

Why might they differ? The 2025 review included adults rather than only men, and “low-fat” was defined as 30% of energy or less, which is not especially extreme. The 2021 review was men only. Study length, calorie balance and baseline fat intake also vary widely between trials.

There is also observational data from athletes. In a small study of 8 strength athletes and 10 active non-athletes, resting testosterone correlated positively with fat intake and negatively with protein intake. The authors suggested that diets with insufficient fat and/or excessive protein may compromise the anabolic hormonal environment over a training program (Sallinen et al., 2004). Correlation in 18 people is a hint, not proof.

So where does 0.6-0.8 g/kg come from?

Honest answer: it is a coaching guardrail, not a number carved in stone. No trial has found that 0.59 g/kg breaks your hormones and 0.61 g/kg saves them.

What we do have is a pattern. The natural bodybuilding review by Helms and colleagues suggests most (not all) lifters in contest prep do well on 15-30% of calories from fat, with protein and carbs filling the rest (Helms et al., 2014). Converted to grams for most body weights and calorie levels, 0.6-0.8 g/kg lands in or near that range, and it leaves room for a mix of fat sources across the day.

Here is what that looks like in grams. (Figures are simple multiplication, shown for planning.)

One catch: percentages and grams drift apart as calories change. A 70 kg lifter on 1,800 kcal who eats 42 g of fat (0.6 g/kg) is at about 21% of calories. A 70 kg lifter on 2,800 kcal at the same 42 g is only 14%. Always check the grams, not just the percentage.

Is cutting fat to near zero worth the calories?

Rarely. Fat has 9 kcal per gram, so it feels like the obvious thing to slash. Drop from 60 g to 20 g and you free about 360 kcal. That is roughly the same as one extra serving of rice and dal, and far less than the diet culture drama suggests.

What you give up is bigger. Meals get less filling. Training fuel gets thinner. Vitamin absorption and essential fat intake may suffer. And a plan you cannot stick to is worth nothing.

The most common mistake here is treating “fat” and “fat gain” as the same thing. Fat gain comes from eating more energy than you burn, not from fat as a nutrient. If your deficit is too aggressive, trimming a few grams of carbs or reducing portion size usually gives the same saving with fewer side effects. To set your total calories, use the calorie calculator, then build macros step by step with our guide to calculating macronutrient splits.

Is it fat, or is it the deficit? Low energy availability

Here is the point many lifters miss. When people crash their hormones on a cut, the cause is often the size and length of the energy deficit, not fat grams alone.

A review of natural male bodybuilding by Fagerberg summarised what can be extrapolated from related research. A prolonged energy availability below about 25 kcal per kg of fat-free mass was linked with muscle loss, hormonal imbalances, psychological problems and cardiovascular effects as athletes approached very low body fat (roughly 4-5%). Case studies of natural male bodybuilders showed muscle loss above 40% of total weight lost with energy availability below 20 kcal/kg FFM. The author noted that no well-controlled studies in natural male bodybuilders exist, so this is extrapolation, and that a more tempered approach (above 25 kcal/kg FFM) might lead to less muscle loss (Fagerberg, 2018).

That matters because very low-fat diets and very low-calorie diets often come as a package. Cut fat to the floor, cut carbs hard, and you end up chronically under-fuelled. Pick the slower option. Helms and colleagues recommend a calorie intake that produces weight loss of about 0.5-1% of body weight a week to maximise muscle retention (Helms et al., 2014).

If you are lean and still pushing, our guide to high protein during a cut covers how to keep muscle on while eating less.

Signs your cut may be too aggressive

None of these prove a hormone problem. Many things cause them, and only a doctor can tell you what is going on. But a pile-up of them is a signal to stop and reassess.

• Libido has noticeably dropped for weeks
• Mood is flat or irritable, with poor motivation to train
• Sleep is bad even when you are tired
• Strength is falling, not just stalling
• You feel cold, light-headed or constantly hungry
• Women: periods become irregular or stop

If this sounds familiar, raise calories first, bring fat back to 0.7-0.8 g/kg or higher, and see a doctor if symptoms last more than a few weeks. Blood tests can check testosterone and other markers properly. Do not self-diagnose from a symptom list, and do not reach for supplements or “boosters” to fix it.

How to hit your fat target in an Indian diet

Fat is easy to under-eat on a typical vegetarian cutting plate of dal, roti, sabzi and rice cooked with a teaspoon of oil. These are rough, label-dependent numbers, so check packs and use a food-tracking app for exact values.

• Cooking oil or ghee: about 4-5 g of fat per teaspoon. Two teaspoons across the day is already close to 10 g. (If you cook with a lot of oil the opposite problem shows up, which we cover in hidden calorie traps in Indian cooking.)
• Whole eggs: roughly 5 g of fat each, if you eat eggs. See eggs in the Indian diet for the cost and cholesterol question.
• Paneer and curd: full-fat versions bring a meaningful amount per serving. Toned versions bring less.
• Peanuts and almonds: a small handful adds around 10-15 g and is cheap in India, especially groundnuts.
• Fish: fatty fish like sardines or mackerel adds omega-3s, and our omega-3 guide covers dosing.

A simple approach: spread fat across three meals instead of loading it all at dinner. That keeps meals satisfying and makes the daily total easy to hit.

What about fat quality?

Once you are above the floor, the type of fat starts to matter more than the exact gram count. Mix sources: nuts, seeds, oils, dairy, eggs and fish. We dig into the heart-health and testosterone angle in saturated vs unsaturated fats, so we will not repeat it here.

Who should talk to a doctor first

Speak to a doctor or registered dietitian before running a very low-fat or very low-calorie plan if you:

• have a history of disordered eating
• are pregnant or breastfeeding
• have gallbladder, pancreas or lipid disorders
• take medication that affects hormones or digestion
• are a teenager still growing

Persistent low libido, missed periods or constant fatigue always deserve a proper check, whatever your macros look like.

The bottom line

A fat intake of roughly 0.6-0.8 g/kg per day is a sensible floor for most lifters, not a magic threshold. The evidence that low-fat diets lower testosterone is mixed: one meta-analysis says modestly yes, another says no. What is clearer is that long, deep deficits with very low energy availability tend to go badly for muscle, mood and hormones.

So keep it simple. Set protein, hold fat at or above the floor, trim carbs and calories modestly, and lose weight slowly. Then use the macro calculator to put real numbers on your plate.