Organization of Dietary Control for Nutrition-Training Intervention Involving Periodized Carbohydrate Availability and Ketogenic Low-Carbohydrate High-Fat Diet

Abstract

The authors describe the implementation of a 3-week dietary intervention in elite race walkers at the Australian Institute of Sport, with a focus on the resources and strategies needed to accomplish a complex study of this scale. Interventions involved: traditional guidelines of high carbohydrate (CHO) availability for all training sessions; a periodized CHO diet which integrated sessions with low and high CHO availability within the same total CHO intake; and a ketogenic low-CHO high-fat diet. Seven-day menus and recipes were constructed for a communal eating setting to meet nutritional goals as well as individualized food preferences and special needs. Menus also included nutrition support before, during, and after exercise. Daily monitoring, via observation and food checklists, showed that energy and macronutrient targets were achieved. Diets were matched for energy (∼14.8 MJ/d) and protein (∼2.1 g·kg·day) and achieved desired differences for fat and CHO, with high CHO availability and periodized CHO availability: CHO = 8.5 g·kg·day, 60% energy, fat = 20% of energy and low-CHO high-fat diet: 0.5 g·kg·day CHO, fat = 78% energy. There were no differences in micronutrient intake or density between the high CHO availability and periodized CHO availability diets; however, the micronutrient density of the low-CHO high-fat diet was significantly lower. Daily food costs per athlete were similar for each diet (∼AU$ 27 ± 10). Successful implementation and monitoring of dietary interventions in sports nutrition research of the scale of the present study require meticulous planning and the expertise of chefs and sports dietitians. Different approaches to sports nutrition support raise practical challenges around cost, micronutrient density, accommodation of special needs, and sustainability.

A Short-Term Ketogenic Diet Impairs Markers of Bone Health in Response to Exercise

“…Participants completed a 3.5-week block of intensified training and laboratory and field testing, supported by either a high-CHO (HCHO) or an isoenergetic LCHF diet (Figure 1, Table 1), consumed under strict dietary control (18). Upon completion of the 3.5-week dietary intervention, a subset of participants (n = 18) completed a further testing block under conditions of acute high CHO availability.…”

“…Details of dietary control are described briefly here; more details are described in prior work (18). Participants were allocated into HCHO and LCHF groups based on preference.…”

Toward a Common Understanding of Diet–Exercise Strategies to Manipulate Fuel Availability for Training and Competition Preparation in Endurance Sport

“…• Restricted food variety with K-LCHF diet (e.g., avoidance of grains and most fruit, limited intake of dairy, seeds, vegetables, and nuts) reduces dietary nutrient density compared with higher CHO diets (Mirtschin et al, 2018).…”

“…Therefore, we propose the following table of definitions and explanations as a starting point for a more unified dialogue (Tables 1-3), and we encourage our colleagues in this area of research and practice to provide as much objective detail as possible about the dietary strategies with which they experiment and apply in the field with athletes. Indeed, this issue contains a methods paper with a lengthy explanation of the principles, practices, and outcomes of organizing a tightly controlled diettraining intervention of this type (Mirtschin et al, 2018). We note that our efforts typically describe the philosophy of different approaches rather than a single/definitive macronutrient prescription.…”

Sports Nutritionists Adopt the Nutrition Care Process (NCP) Road Map to Develop Individualized Meal Planning for Athletes.

“…A study by Ducrot et al (2017) found that meal planning is one of the dietary interventions associated with adherence to nutrition guidelines and the consumption of a variety of food groups (9). A dietitian's or nutritionist's expert knowledge on food composition is required to translate nutrition prescriptions into food choices and choice of meal times (10). In addition, other factors that in uence food choices among athletes should also be considered such as taste, convenience, nutrition knowledge and beliefs (11).…”