F45-style training is a 45-minute circuit format alternating resistance and cardio stations in a group setting. It is short, frequent and time-pressured, which makes the nutrition problem practical rather than exotic: most members train three to five times a week around work, and the meals that decide their results are the ones eaten in the 30 minutes after class. Keep protein consistent, keep total energy matched to your goal, and put carbohydrate around your hardest sessions.
The defining features are short duration, station-based circuits mixing resistance and conditioning, and high weekly frequency. Because sessions are brief, single-session fuelling is rarely the limiting factor — weekly consistency is.
Where people go wrong is at the edges: training early on nothing and then eating nothing until 11am, or finishing an evening class starving with no food in the house.
45 minutes of alternating resistance and cardio stations, often with short work-to-rest ratios.
Attendance is typically high frequency, so cumulative recovery matters more than any single class.
Resistance stations create a real, if moderate, muscle-building stimulus — protein counts.
Class timing, not macronutrient detail, is the dominant real-world constraint.
What the evidence says
There is no meaningful body of F45-specific nutrition research, and this page will not invent one. What applies is general evidence: the ISSN position stand supports roughly 1.4–2.0 g/kg/day of protein for exercising people, and pooled resistance-training data show benefits of added protein plateauing near 1.6 g/kg/day.
For the conditioning stations, carbohydrate availability supports high-intensity work (PMID 42070893), and a systematic review of high-intensity functional training describes the mixed aerobic-anaerobic stress of this style of session while noting the limited quality of nutrition research in it.
How strong is this evidence? Branded challenge programmes often bundle aggressive calorie targets with class attendance. Those targets are marketing constructs, not validated protocols — be cautious, and get individual advice before following an aggressive deficit.
Little or nothing is fine for most people at 45 minutes. A small carbohydrate snack helps if you feel flat.
After class
Protein plus carbohydrate. For 6am classes this is breakfast; for evening classes it is dinner, and it should already exist.
Across the week
Protein at every meal is the single highest-yield habit.
Match total energy to your goal rather than trying to out-train an unplanned diet.
Real SmashMeals examples
Real SmashMeals menu-snapshot items with published macros — protein-forward plates that reheat quickly, which is the whole game for a 45-minute-class schedule. Menu availability rotates weekly.
Turkey Taco Cauliflower Bowl — 7 oz — 300 cal, 38g protein, 8g carbs, 15g fat — Lean seasoned turkey served over cauliflower rice with peppers, onions, salsa, and a light sprinkle of cheese. Big taco flavor in a smaller, lower-carb bowl.
Lemon Herb Chicken & Cauliflower Mash Plate — 7 oz — 290 cal, 36g protein, 12g carbs, 8g fat — Tender lemon herb grilled chicken served with creamy cauliflower mash and roasted green beans. A smaller, high-protein, lower-carb plate built for customers who want something clean, filling, and easy to digest.
Chicken Burrito Bowl with Jasmine Rice — 448 cal, 36g protein, 36g carbs, 17g fat — Jasmine rice, topped with salsa chicken, cheese, side of lime and sour cream
Smore's Protein Pudding — 325 cal, 35g protein, 31g carbs, 9g fat — Greek yogurt, vanilla protein powder, dark chocolate chips, mini marshmallows, gluten free graham cracker crumbs
Hard Boiled Eggs — 234 cal, 19g protein, 2g carbs, 16g fat — 3 hard boiled eggs .
Examples from the SmashMeals menu and archive. The menu rotates weekly — check this week's menu.
An example F45 week
Morning class day
Optional small pre-class snack; protein-and-carbohydrate breakfast straight after; balanced lunch and dinner.
Evening class day
Normal breakfast and lunch; light afternoon snack; ready-made protein dinner afterwards.
Off day
Same protein pattern; fewer starch-heavy sides if fat loss is the goal.
An example framework, not a prescription.
Where gluten-free actually fits
Everything is cooked in a dedicated 100% gluten-free kitchen, which matters if you need or choose gluten-free meals. It is not a performance benefit for people without a medical or individual reason to avoid gluten.
Frequently asked questions
Should I eat before a 6am F45 class?
Most people are fine without food for a 45-minute session. If you feel weak in the last rounds, try a small carbohydrate-containing snack beforehand and see whether it helps.
How much protein do I need doing F45 five times a week?
General guidance for exercising adults is roughly 1.4–2.0 g per kilogram of body weight per day. Frequency does not change the range much; consistency does.
Are challenge-programme calorie targets safe?
They are generic by design and may be too aggressive for some people. If a target feels extreme, or you have a health condition, check it with a dietitian or clinician before following it.
What is the easiest meal-prep setup for class-based training?
Cover the two meals that follow your classes and leave the rest flexible. That is usually enough structure to change results without turning eating into a second job.
Sources
Independent research
ISSN position stand: protein and exercise (Jäger et al., 2017) — PubMed / JISSN. Resistance exercise and protein intake both stimulate muscle protein synthesis; roughly 1.4–2.0 g of protein per kg of body weight per day is sufficient for most exercising people.
Nutrition needs vary with body size, training volume, goals, health conditions and competition demands. For individualised performance or medical nutrition, work with a qualified sports dietitian or clinician.
Editorially reviewed by SmashMeals for source accuracy in September 2026. This page is written from published research and official format documentation; it is not medical or individualised sports-nutrition advice, and no clinician reviewed it.
SmashMeals is not affiliated with, sponsored by, or endorsed by F45 Training. This page describes circuit-style class training generically and cites independent research only.