Case Study: Undereating, Low Energy, and Recovery in an Active Dad

Case Overview

A.S. is a 30-year-old male, 6’5”, 180 pounds, and highly active. His exercise routine included five days per week of heavy weightlifting, light cardio, and recreational sports like basketball, football, soccer, and softball. He had recently been recovering from a lower back injury and was eager to return to full training.

Despite his commitment to fitness, he struggled with low energy, afternoon crashes, sugar cravings, headaches, and mood swings. His busy lifestyle included frequent work travel and disrupted sleep due to caring for two young children (ages three years and eight months). He also had little appetite in the mornings, often skipping breakfast despite training at 5:30 a.m., and delaying his first meal until lunchtime.

Clinical Findings

Food tracking revealed that A.S. was severely undereating. On some days, his intake dipped as low as 1,200 calories, far below what someone of his height, activity level, and muscle-gain goals required.

Pertinent Labs

Vitamin D: Low at 28 ng/ml
Vitamin B12: Low at 345 pg/ml
Iron: Low/normal at 50 ug/dl with a low ferritin of 18 ng/ml

For his size and training schedule, he needed closer to 2,800–3,000 calories per day, with at least:

Protein: ~150 g/day
Carbohydrates: ~280 g/day
Fat: ~120 g/day

Intervention

The focus was on rebuilding his nutritional foundation:

Added a protein-rich breakfast: even though he had little appetite in the morning, we emphasized that hunger would reset within a few days once his body adjusted.
Balanced meals: distributing calories and macronutrients more evenly across breakfast, lunch, and dinner instead of undereating all day and then overeating later.
Whole-food focus: roughly 16 oz of animal protein daily, six cups of starchy vegetables/fruits, and added healthy fats like olive oil or avocado at each meal.
Targeted supplementation: While he worked to improve his diet, we also added Vitamin D with K 5,000 IU daily, Trifolamin lozenge and dessicated liver capsules to help bridge the nutrient gap

Results

After just a few days, A.S. reported:

Increased energy
Elimination of sugar cravings, headaches, and mood swings
Better gym performance and recovery
Improved ability to sustain five days of training without energy crashes

Though he initially found it difficult to increase his calorie intake, after a few weeks his appetite normalized and he felt satisfied after meals.

Results after 3 months:

Reported improved energy levels, resolution of headaches, improved exercise recovery and less brain fog
Vitamin D improved to 50 ng/ml
Vitamin B12 improved to 1356 pg/ml
Iron improved to 112 ug/dl and ferritin to 80 ng/ml

Takeaway

This case illustrates how undereating (especially in active individuals) can lead to fatigue, cravings, mood changes, and poor recovery. Prioritizing consistent, balanced meals with adequate protein and calories restored A.S.’s energy and performance within weeks.