What is the BMR for a 45-year-old man?

The estimated BMR (basal metabolic rate) for a 45-year-old man of average height and weight is 1764 kcal/day, calculated using the Mifflin-St Jeor equation.

Calorie Guide · Age 45

Calories for a 45-Year-Old Man

Q: How many calories does a 45-year-old man need?

A lightly active 45-year-old man of average weight and height needs approximately 2425 kcal/day to maintain weight. Sedentary needs are around 2116 kcal, and very active around 3042 kcal.

Q: How many calories should a 45-year-old man eat to lose weight?

A 45-year-old man should eat approximately 1925 kcal/day to lose about 0.5 kg (1 lb) per week. This is a 500 kcal deficit from the estimated maintenance of 2425 kcal.

BMR, TDEE and exact calorie targets for weight loss, maintenance and muscle gain at age 45.

Calorie Needs at Age 45 — Average Man

1764

BMR (at rest)

2116

Sedentary TDEE

2425
Lightly active TDEE

2734

Moderately active

1925

Weight loss target

2425

Maintenance

2725

Muscle gain target

How Many Calories Does a 45-Year-Old Man Need?

Using the Mifflin-St Jeor equation with average US height and weight for a man aged 45, the resting metabolic rate (BMR) is approximately 1764 kcal/day. With typical daily activity included, total calorie expenditure (TDEE) ranges from 2116 kcal (sedentary) to 3042 kcal (very active).

Age 45 note: After 40, muscle loss (sarcopenia) accelerates if untrained. Strength training 2–3×/week and higher protein intake (1 g/lb) are the most effective countermeasures.

Calorie Targets by Goal

Goal	Daily Calories	Expected Result
🔵 Aggressive weight loss	1675 kcal	~0.75 kg/week
📉 Weight loss	1925 kcal	~0.5 kg/week
✅ Maintenance	2425 kcal	Weight stable
💪 Lean bulk	2725 kcal	~0.25 kg/week
🏋️ Aggressive bulk	2925 kcal	~0.5 kg/week

Calorie Needs by Activity Level

Activity Level	Description	Daily Calories
Sedentary	Desk job, minimal movement	2116 kcal
Lightly active	1–3 workouts/week	2425 kcal
Moderately active	3–5 workouts/week	2734 kcal
Very active	Hard training 6–7 days/week	3042 kcal

How Metabolism Changes Around Age 45

Metabolic rate declines approximately 1–2% per decade after age 30, driven primarily by muscle loss (sarcopenia) rather than any inherent slowdown. At age 45, your BMR of 1764 kcal reflects your current muscle mass, height and hormonal status. The single most effective way to maintain or raise your BMR is resistance training — each kilogram of lean muscle burns roughly 13 kcal/day at rest.

Age	Estimated BMR (man)	Change vs age 45
35	1814 kcal	+50 kcal
40	1789 kcal	+25 kcal
45	1764 kcal	—
50	1739 kcal	-25 kcal
55	1714 kcal	-50 kcal

Macronutrient Split at 2425 kcal

Macro	% of Calories	Grams/day	Calories
Protein	30%	182 g	728 kcal
Carbohydrates	40%	242 g	968 kcal
Fat	30%	81 g	729 kcal

At age 45, protein intake is especially important. Aim for at least 71–89 g/day to maintain muscle mass, whether you're in a deficit, at maintenance, or in a surplus.

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Frequently Asked Questions

How many calories does a 45-year-old man need per day?A lightly active 45-year-old man of average size needs approximately 2425 kcal/day to maintain weight. This ranges from 2116 kcal (sedentary) to 3042 kcal (very active).

How many calories should a 45-year-old man eat to lose weight?Aim for 1925 kcal/day — a 500 kcal deficit from the 2425 kcal maintenance estimate — to lose approximately 0.5 kg per week. Never go below 1200 kcal (women) or 1500 kcal (men) for extended periods.

Does age 45 affect how many calories you burn?Yes. Every decade after 30, BMR drops ~1–2% mainly due to muscle loss. At age 45 the estimated BMR is 1764 kcal — compare to 1839 kcal at age 30. Resistance training largely offsets this decline.

Related Age Guides

Sources

WHO CDC Mifflin-St Jeor (PubMed)