A 28-Day Carbohydrate-Restricted Diet Improves Markers of Cardiovascular Disease in Professional Firefighters

Abstract

Waldman, HS, Smith, JW, Lamberth, J, Fountain, BJ, Bloomer, RJ, Butawan, MB, and McAllister, MJ. A 28-day carbohydrate-restricted diet improves markers of cardiovascular disease in professional firefighters. J Strength Cond Res 34(10): 2785–2792, 2020—This study compared the effects of a 4-week, nonketogenic, carbohydrate-restricted (<25% of calories) diet (CRD) on markers of inflammation and oxidative stress in professional firefighters (FF). Subjects (n = 15) reported to the laboratory for 2 sessions (i.e., baseline and post-CRD) where blood was drawn from an antecubital vein after a 10-hour overnight fast. Dependent variables measured at baseline and post-CRD included adiponectin, insulin, human growth hormone, cortisol, C-reactive protein, albumin, lipids, glucose, amylase, creatine kinase, malondialdehyde (MDA), advance oxidation protein products (AOPP), total nitrate + nitrite, and soluble intracellular adhesion molecule-1. Compared with baseline, the CRD resulted in dramatic improvements to subjects' cardiometabolic profiles, including decreases in AOPP (51.3 ± 27.3 vs. 32.9 ± 7.9 ng·ml−1), MDA (1.6 ± 0.6 vs. 1.1 ± 0.5 µmol·L−1), and triglycerides (84.4 ± 34.4 vs. 64.2 ± 14.4 mg·dl−1), respectively. In addition, the CRD increased total cholesterol (151.5 ± 23.0 vs. 167.7 ± 38.2 mg·dl−1) and high-density lipoprotein cholesterol (46.3 ± 12.7 vs. 50.6 ± 15.5 mg·dl−1), but no differences were found with low-density lipoprotein cholesterol. Overall, our results show a 4-week CRD can favorably improve some markers of cardiovascular health in male FF.

Dietary Behavior and Diet Interventions among Structural Firefighters: A Narrative Review

“…Moreover, it may lead to CVD risks due to increases in LDL cholesterol and very-low-density lipoprotein [ 52 ]. Another study by Waldman et al [ 47 ] used biomarker measurements to further assess the utilization of a 28-day CRD to improve cardiometabolic health. Their results suggest that a 28-day CRD can improve biomarkers of CVD.…”

Deterioration of Lipid Metabolism Despite Fitness Improvements in Wildland Firefighters

“…35 The preparatory critical training phase for WLFFs 33,34 and the Alaskan backcountry hunting expeditions [33][34][35][36] differ in the availability or consumption of dietary nutrients, wherein WLFFs are typically well fed but Alaskan backcountry hunters experience high levels of energy deficit (À 10 to -9 MJ day À1 ). Variations in energy balance are therefore important in that multi-day bouts of moderate intensity physical activity typically produce favorable outcomes in serum lipid remodeling and body composition changes 37 ; a finding that does not appear to result following the multifactorial stressors associated with seasonal wildfire suppression.…”

International society of sports nutrition position stand: tactical athlete nutrition

“…Due to the small sample size and limited duration, more research is needed to further explore the potential impact a low-carbohydrate diet may have on the health and performance of first responders. In addition, a notable observation by Waldman et al [ 310 ] highlighted the previous findings by Yang et al [ 295 ] that indicated firefighter populations prefer a diet higher in animal proteins, which may increase feelings of satiety and naturally decrease overall caloric intake. Therefore, it is likely not the decrease in carbohydrates but rather the increase in protein consumption that makes the adoption of a CRD an effective nutrition intervention for fire communities.…”