Adiposity Nadir
Use the Adiposity Nadir Calculator → Try the Adiposity Nadir Quiz →What is Adiposity Nadir?
The adiposity nadir is the lowest point in a child's BMI trajectory - the trough of the U-shaped curve that characterizes normal childhood development. From birth, BMI rises steeply, then falls through toddlerhood and early childhood as height growth outpaces weight gain. The nadir is the bottom of this dip, typically occurring between ages 4 and 6.
After the nadir, BMI begins its long rise through childhood and adolescence - the phase known as adiposity rebound. The age at which the nadir occurs is a key prognostic marker: children who reach their nadir early (before age 5) tend to begin rebound earlier and accumulate more adipose tissue over the following years, compared to children whose nadir occurs at age 6 or later.
When to use Adiposity Nadir
Look for the adiposity nadir when reviewing a child's BMI growth chart across consecutive visits. The nadir is the lowest point on that curve - the moment before the upward trend of adiposity rebound begins. Because it can only be identified in retrospect (after the subsequent rise confirms the turning point), tracking BMI at every well-child visit is essential for spotting an early nadir before the trend becomes firmly established.
Worked examples for Adiposity Nadir
This table quickly gives you the overview you need to understand Adiposity Nadir and its most important comparisons.
| Nadir age | Rebound onset | Long-term implication |
|---|---|---|
| Before age 5 (early) | Before age 5 | Early rebound; higher adult obesity risk even at a normal current percentile |
| Ages 5-6 (typical) | Ages 5-7 | Average trajectory; standard monitoring appropriate |
| After age 7 (late) | After age 7 | Late rebound; associated with lower adult obesity risk |
Common pitfalls
The adiposity nadir can only be confirmed in retrospect - you cannot know the nadir has been reached until the subsequent upward trend of adiposity rebound makes it clear. A single BMI reading, no matter how low, cannot confirm the nadir. This is why sequential measurement at each well-child visit is essential. A second pitfall: a low nadir BMI value is not inherently protective - what matters clinically is the age of the nadir, not the value.
Frequently asked questions about Adiposity Nadir
What is the adiposity nadir?
The adiposity nadir is the lowest point in a child's BMI curve, typically occurring between ages 4 and 6. It marks the end of the early-childhood fall in BMI and the beginning of the adiposity rebound. The age at which a child hits their nadir is more clinically important than the BMI value at that point.
What is a typical BMI at the adiposity nadir?
It varies by age and gender. At age 5, the CDC 2000 median (50th percentile) is approximately 15.5 for boys and 15.2 for girls. The nadir is not defined by a specific BMI number but by the inflection point in the child's individual growth curve - the value at which BMI stops falling and begins to rise.
Is a lower nadir BMI value better for long-term health?
Not necessarily. The nadir BMI value is less prognostically important than the age at which it occurs. A child with a low nadir BMI who reaches it before age 5 may carry higher long-term obesity risk than a child with a slightly higher nadir BMI who reaches it at age 6 or 7. Timing is the signal, not the value.
How does the adiposity nadir relate to adiposity rebound?
They are two phases of the same developmental process. The nadir is the lowest point; adiposity rebound is the subsequent rise. The nadir ends when rebound begins. Clinically, the nadir's significance lies entirely in when it occurs - an early nadir (before age 5) means an early rebound and a longer window of gradual fat accumulation before adulthood.
Quiz: how well do you know adiposity nadir?
1. What is the adiposity nadir?
2. After the adiposity nadir, what typically happens to a child's BMI?
3. What makes the age of the adiposity nadir clinically significant?
4. Why can the adiposity nadir only be identified in retrospect?