Fat loss for resistance-trained athletes. What is effective?

Summary of a narrative review looking at effective strategies to address fat loss in resistance-trained athletes from bodybuilding, weightlifting and powerlifting.

Who

Resistance-trained athletes from bodybuilding, weightlifting and powerlifting.

Design

Narrative review.

Outcome measures

• weight loss
• fat loss

Main results

• Energy intake
  • weight loss requires energy deficit between intake and expenditure.
  • energy expenditure = exercise activity thermogenesis (EAT) and non-exercise activity thermogenesis (NEAT)
  • fat free mass (muscles) is preserved better if the weight loss is kept within 0.5% of body weight per week (when compared with 0.7% or 1% loss of body weight per week).
  • for women, optimal energy intake is 45 kcal/each kg of fat-free mass/day. Energy intake below 30 kcal/kg of fat-free mass/day may result in hormonal changes, and menstrual cycle disturbances.
  • for men, energy intake of less than 25 kcal/each kg of fat-free mass/day can alter hormonal levels, trigger psychological problems and in case of low fat % (4-5%) it can cause cardiovascular issues.
  • diet break - a 1-2 weeks phase of caloric intake at maintenance levels (caloric levels allowing for keeping the weight stable, not increasing and not decreasing) which is interrupting the prolonged caloric deficit diet.
• Macronutrients
  • protein:
    • protein requirements at maintenance are about 1.6 g/each kg of body weight/day
    • for athletes performing resistance training and in calories’ restriction, protein intake should be around 2.3-3.1 g/each kg of fat-free mass/day or 1.6-2.4 g/each kg of body weight/day. The intake should be higher when caloric deficit is kept higher and/or the athlete has lower body fat % (since there is less calories’ reserves available). Intake of more than 2.6 g of protein/each kg of body weight/day did not improve results.
    • high-protein meals improve the feeling of fullness, which may increase adherence to the diet with restricted calories.
  • carbohydrate:
    • strength training session depletes 24-40% of glycogen stores in muscles
    • in the fat loss phase 2-5 g /kg BW/day of carbohydrates is recommended
    • ketogenic diet can be helpful in fat reduction because it seems to preserve strength (although the muscle mass is still lost)
    • fiber recommended consumption is 25g/day
  • fat:
    • diets with <20% of fat intake may reduce testosterone levels
    • fat intake of 20-30% is recommended or at least 0.5 g/kg BW/day
    • in maintenance phase, diets with high protein and carbohydrate intake and low fat had better results than diet with high protein and fat but low carbohydrates.
• Nutrient timing
  • protein before bed may be a good idea especially if the protein requirements are not met during the day. This will increase muscle protein synthesis as a response to resistance exercise.
  • each protein serving should be at least 0.4-0.55 g/kg BW (0.6 g/kg BW in elderly) to meet leucine content requirement of ≥1-3 g.
  • as strength training does not deplete glycogen stores as much as endurance training, there is no need to time the carbohydrate intake as long as daily requirements are met. Unless there are two sessions a day
  • protein intake starts to stimulate muscle protein synthesis after 45-90 minutes and reaches maximum at 90-120 minutes, and then goes back to baseline (“muscle full effect”). However, this can be extended after the exercise session.
  • co-intake of protein and carbohydrates does not change adaptations to resistance training.
• How often should I eat:
  • as it fits the lifestyle. No difference between the number of meals as long as the caloric and macronutrient requirements are met.
• Micronutrients
  • weightlifters often ingest less than recommended vitamins B1, B3, B6, B9, and magnesium, calcium, and potassium. In general, dieting populations are notorious for not meeting the essential micronutrient intake. Therefore, prophylactic use of low-dose multi-micronutrient supplements may be worth considering.
• Creatine monohydrate
  • improves muscle phosphocreatine concentration, reduces muscle acidosis occurring during high-intensity exercises, and improves muscle mass and strength gains.
  • if load is required: 5-7 days of 0.30 g/kg BW of creatine monohydrate, and 0.08-0.10 g/kg daily after that
  • if no load phase: just 0.08-0.10 g/kg daily to reach saturation muscle creatine levels in 28 days.
  • creatine can potentially interfere with caffeine.
• Caffeine
  • improves muscle strength and power mostly expressed in upper body.
  • for fatigue reduction: 1-3mg/kg BW/day
  • to improve strength performance: 3-6 mg/kg BW/day, 30-60 minutes before training
  • everyone responses differently though, so the individual level should be found.
  • caffeine can potentially interfere with creatine.
• Daily intake recommendations during a fat loss phase in strength athletes:
  Component

  Target fat loss

  Protein

  Carbohydrate

  Fat

  Creatine

  Caffeine

  Multi-micronutrient supplements

  Recommended intake

  Component

  Target fat loss

  0.5% of BW/week

  Protein

  2.2–3.0 g/kg BW/day

  Carbohydrate

  2–5 g/kg BW/day

  Fat

  ≥0.5 g/kg BW/day

  Creatine

  0.08–0.10 g/kg BW/day

  Caffeine

  3–6 mg/kg BW/day

  Multi-micronutrient supplements

  possibly once a day

Take home message

Original article

Ruiz-Castellano C, Espinar S, Contreras C, Mata F, Aragon AA, Martínez-Sanz JM. Achieving an Optimal Fat Loss Phase in Resistance-Trained Athletes: A Narrative Review. Nutrients. 2021 Sep;13(9):3255.

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