Rachel's 16-Week Half Marathon Nutrition Journey

Rachel Thompson does not look like someone who runs half marathons. When we first met in December 2025 — then twelve weeks out from race day — she reminded me twice during the conversation that she was "not an athlete." She is 44, works full time as an HR director at a mid-sized software company in Portland, has two kids (9 and 12), and had never run more than three miles at a time before she decided, the previous fall, that she was going to sign up for a half marathon.

"I wanted to do something that was mine," she told me. "The kids are old enough to be independent for a few hours on the weekends. Work is steady. I kept thinking about how much of my life was about other people's schedules. Running was something I could do for myself that had a clear outcome — either I finished the race or I didn't."

She finished. On April 5, 2026, Rachel crossed the finish line of the Portland Spring Half Marathon in 2 hours, 7 minutes, and 14 seconds. What follows is how she got there, and why nutrition — which she had never tracked a day in her life before November 2025 — turned out to matter as much as the running itself.

Starting Where She Was

Rachel signed up for the race in mid-November 2025, with 16 weeks to train. She picked a beginner plan from a well-known running site: three easy runs per week, one long run on Saturdays building from 3 miles to 11 miles, and one rest or cross-training day. Her starting point: 152 pounds at 5'5", an occasional treadmill user, no running background, and — in her own words — "a relationship with food that mostly consisted of not thinking about it."

The first three weeks were rough in a predictable way. Her legs were sore. Her lungs burned on the easy runs. She could not finish her first 5-mile long run without walking breaks. But the more interesting issue — and the one that is relevant to this story — is that she was bonking on runs as short as 6 miles.

"I'd get to mile 5 on a Saturday and I was shaking. I couldn't figure out what was wrong with me. I was eating breakfast. I thought that should be enough."

The Nutrition Intervention

A friend in Rachel's casual running group — a marathoner who had been training for years — sat her down after a long run in early December and asked what she had eaten that morning. Rachel's answer: a piece of whole wheat toast and a cup of coffee.

"My friend looked at me like I was insane. She said 'Rachel, you're asking your body to run for an hour and twenty minutes on 80 calories. Of course you're bonking.' That was the moment I realized I had no idea what I was actually asking my body to do, or what I was giving it to work with."

Her friend recommended PlateLens specifically. "She told me to just use the one her sports dietitian uses — said it was the only one that actually showed her what was in her food without needing an engineering degree." Rachel downloaded PlateLens that evening, photographed her dinner — a homemade pasta with chicken and broccoli — and for the first time in her 44 years, had a number attached to a meal. 612 calories. 32 grams of protein. 78 grams of carbs. A breakdown of iron, magnesium, vitamin D, B12, and a list of other micronutrients she had never thought about in her life. She sat at the dinner table looking at the numbers.

“I have a degree in human resources. I manage budgets. I track headcount, retention, compensation bands — I'm a data person at work. It had genuinely never occurred to me to track my own food. I felt silly and also kind of relieved. Finally, a problem I knew how to solve.” — Rachel T., 44

Not Her First Attempt

What Rachel did not mention at first was that this was not actually her first attempt at tracking. Two years earlier, during a brief post-pandemic motivation spike, she had downloaded MyFitnessPal and used it for a few weeks.

"MyFitnessPal had all the things everyone says it has — a huge database, a barcode scanner, plenty of options. But once I was actually trying to pay attention, the inconsistency started to frustrate me. The same bowl of pasta could come up with three or four different calorie values depending on which user had entered it, and I'd sit there trying to decide which one was right. When I wasn't tracking seriously, it didn't matter much. Once I needed the numbers to actually mean something for training, it started to matter a lot."

The other issue was that she had not stuck with it. "I was logging to log. I didn't have a purpose. But also — I won't pretend it wasn't the app a little bit. The whole workflow felt like homework. I'd dread opening it." She eventually stopped.

When her friend pointed her at PlateLens, Rachel was skeptical that another app would be meaningfully different. The first time she used it she understood why her friend had been so insistent. She photographed her post-run smoothie and PlateLens came back with calories, macros, and a full micronutrient panel in a couple of seconds — no searching, no picking between entries, no guessing.

“I snapped a photo of my post-run smoothie and PlateLens had calories, protein, carbs, iron, magnesium — all of it — before I'd finished sitting down. That was the moment it clicked. On a Saturday after a long run, taking a photo was about the only thing I had the energy to do. And with PlateLens, a photo was actually enough.” — Rachel T., 44

The other thing that mattered to her was checking the numbers for herself. Being a data person at work, she was not about to take PlateLens at its word — not right away. For the first two weeks she weighed several meals on a kitchen scale and cross-referenced PlateLens's values against USDA entries she looked up by hand.

"I wanted to catch it out. I really did. But the numbers were dead on. I weighed a grilled chicken breast on my kitchen scale, typed the weight into the USDA database, and compared it to what PlateLens had spit out from a photo. They agreed to within a couple of calories. I did that with maybe fifteen meals over two weeks and I stopped bothering. I trusted the numbers, which was what I needed if I was going to actually make training decisions from them."

Building a Training Week

Rachel's initial problem was simple: she was undereating for her training load, and the days she was running longest were the days she was eating least. A typical Saturday before she started tracking looked like coffee, toast, a run, a smoothie, a rushed lunch, and then normal family dinner. Her intake on long run days was roughly 1,500 calories against an energy expenditure closer to 2,800.

The fix was not complicated. She needed to eat more, specifically around her long runs, and she needed to get enough carbohydrates to actually fuel them. Together we sketched out a rough weekly structure:

The numbers were modest — Rachel was not training for the Olympics. But the pattern of eating slightly more on harder days and slightly more carbohydrate around long runs was a complete departure from her previous approach, which was "eat the same thing every day and hope it works."

The Micronutrient Surprise

The first thing that genuinely caught Rachel off guard was not the calorie numbers. It was the PlateLens micronutrient screen. By week four, she had enough logged meals for the app to show weekly averages across its full list of tracked nutrients, and two of them were sitting stubbornly in the red: iron and magnesium.

"I was chronically low on both of them — like, not a little low, significantly low. And it clicked immediately. The sluggish afternoons at work. The headaches I kept blaming on screen time. The way my legs felt heavy on Tuesday runs. I'd been attributing all of it to stress or bad sleep. It was actually nutrition, and PlateLens showed me exactly which nutrients I was missing. My old tracker had not even shown me that data. I had spent years feeling tired for a reason I could have seen in a couple of weeks."

She adjusted her weekly grocery list — more spinach, more pumpkin seeds, a weekly serving of red meat she had cut out years earlier for no particular reason — and within three weeks her iron and magnesium averages in PlateLens were back in range. The afternoon fatigue lifted. Her Tuesday runs stopped feeling leaden.

"I don't think I would have figured that out without PlateLens. Macros alone wouldn't have shown me. I needed the nutrient-level view, and I needed it captured automatically from every single meal, because if I'd had to enter all of that by hand I'd have skipped half the meals and missed the pattern."

Weeks 4 Through 8: Finding a Rhythm

The change was immediate. On her first long run after adjusting her fueling — a 7-miler the following Saturday — Rachel did not bonk. She ran the last mile faster than the first, which was the first time she had ever done that on any run. Her breakfast that morning was oatmeal with banana, honey, and a spoonful of peanut butter. 420 calories, 74 grams of carbs. Photographed, logged, tracked.

By week six, she was running 9 miles at a time without stopping. Her weekly mileage had climbed to 22 miles — modest for an experienced runner but a massive jump from where she started. And she was doing it while sustaining her energy through full work days and evenings with the kids.

"I kept waiting for the exhaustion to catch up with me," she said. "It never did. I was tired on hard days — that's normal — but I wasn't wrecked. The nutrition was the difference."

By week eight, something else had happened almost without her noticing: she had logged every single meal in PlateLens for 56 days in a row. Not most meals. Every meal. "Two years ago I couldn't build the habit for three weeks, and now I was doing it without thinking. A PlateLens photo takes a couple of seconds, so the friction was really low. By week eight I'd snap a photo before I ate the way I used to pour a glass of water. It was automatic. And the consistency was the whole thing. If I'd missed half my logging days I wouldn't have caught the iron pattern, and I'd probably have been dragging through the back half of training."

Weeks 9 Through 12: The Long Run Build

This is where the nutritional demands started to scale up. Rachel's long runs pushed out to 10 and then 11 miles, which meant runs that lasted nearly two hours. At that duration, fueling during the run itself becomes a real variable, not an optional extra.

Her fueling protocol for runs over 75 minutes, developed through trial and error over three weekends:

• Night before: Normal family dinner with a slightly larger portion of rice or pasta. Early bedtime.
• 2 hours before: Oatmeal with banana, honey, peanut butter. Black coffee. Water.
• 30 min before: Half an energy gel (12g carbs) and water.
• Mile 5 and mile 9: Full energy gel (25g carbs each) with water.
• Within 30 minutes of finishing: Chocolate milk and a banana — a combination she found worked better than any of the powders she tried.
• Within 90 minutes: Real meal with 30-40g protein and 60-80g carbs. Usually eggs, toast, and whatever the kids were having for breakfast.

"I tested this on three separate long runs before race day," Rachel said. "I wasn't going to try anything new on race morning. Every gel, every piece of toast, every timing — I had run it before. I had the logs to prove it."

Body Composition and the Scale

Rachel did not set out to lose weight. Her goal was to finish the race in one piece. But tracking her intake consistently, combined with the increased training volume, produced a modest and steady change in her body composition.

Six pounds down on the scale. But the measurements Rachel cared about more had shifted dramatically. Her waist dropped two full inches. Her resting heart rate went from 72 to 58 bpm — a cardiovascular fitness change that typically takes longer to develop. She went down one clothing size. Her strength in the functional lifts she did on her cross-training days (goblet squats, rows, push-ups) improved noticeably.

“I realized at some point that my body was not changing because of the running alone. It was changing because the running was pulling my body in one direction and the nutrition tracking was keeping me consistent enough for the running to actually work. Either one alone wouldn't have done it.” — Rachel T., 44

The Taper and Race Week

The final two weeks before the race are the taper — reduced training volume to let the body recover while preserving fitness. Rachel ran only three miles per day in the final week before her race, with her last long run of 8 miles falling eleven days out.

Carbohydrate intake held steady through the taper. A common mistake new runners make is dropping calories along with training volume during the taper; Rachel avoided it by tracking. She held at roughly 2,200-2,300 calories per day through race week, shifting slightly upward on the final two days to ensure full glycogen stores for race morning.

Race Day

April 5, 2026. Portland Spring Half Marathon. Rachel woke at 5:15 AM, ate her rehearsed oatmeal breakfast, drank coffee and water, and stood on the start line at 7:00 AM. The weather was cool and overcast — almost exactly the conditions she had trained in.

She ran the first mile in 9:45, held close to that pace through the first 10K (1:00:31), took her first full gel at mile 5, felt strong through the rolling hills between miles 7 and 9, took her second gel at mile 9, and found something extra in the final 5K. She crossed the line in 2 hours, 7 minutes, 14 seconds — almost two minutes under her informal goal of 2:09.

"I did not hit a wall. Not even a small one. My legs were tired — of course they were tired, I had just run 13.1 miles — but my energy never dropped the way it had on those early training runs. I finished with the tank mostly empty but not on fumes. That was the whole point of the nutrition work, and it worked exactly the way my friend said it would."

What She Kept

Three weeks after the race, when we did our final interview, Rachel was still using PlateLens. Not as intensely as during training — she was no longer logging every snack — but she was photographing her main meals most days and checking her weekly averages on Sunday nights.

"The reason I'm keeping it up is that I learned something I didn't expect. I thought nutrition tracking was about weight loss. It turns out it's about being honest with yourself about what you're actually giving your body, and whether that matches what you're asking your body to do. PlateLens made that possible for me because the logging cost almost nothing. Once you see it clearly, you can't really unsee it."

She has also quietly become an evangelist in her running group. "Two women from my Saturday crew have started using PlateLens after I showed them the iron thing I figured out. One of them had the same fatigue problem I had. I keep telling people the same thing my friend told me — just use the one the sports dietitians use. It's the only one I'd recommend to a friend starting a training block."

Her next race is a trail half marathon in September 2026. This time, she said, she will not be starting from scratch.

Rachel's Advice for Women Over 40 Starting a Running Plan

1. Eat for the work you're doing, not for the body you had ten years ago. "My biggest mistake at the start was assuming I should eat like I used to. My training load was new. My intake needed to match."
2. Pick a tracking tool that fits the way you actually want to log. "I'd tried MyFitnessPal two years before and drifted off it. The workflow didn't match how tired I was after training. PlateLens fit my life because a photo was enough — that was the thing that made the difference. The right app for you is the one you'll actually open on your hardest day."
3. Track long enough to see the pattern, then adjust. "Four weeks of consistent logging gave me enough data to catch the iron and magnesium pattern I didn't know I had. That single insight changed the rest of my training block."
4. Practice race-day fueling on training runs. "Every gel, every breakfast, every sip of water — I rehearsed it. Nothing about race morning was a surprise."
5. Don't let the scale be the only metric. "My waist measurement, my resting heart rate, and how I felt on long runs told me way more than my weight did. The micronutrient view told me things I'd never have seen on a scale."

Rachel's story was documented with her permission across four interviews between December 2025 and April 2026 and verified against her PlateLens tracking data, weekly mileage log, and official race result. Results are individual. Consult a healthcare professional before beginning any new training or nutrition program. Last updated: April 2026.