A similar fat loss occurred when using a lighter weight training protocol to failure and a heavier weight training protocol.
TRAINING WITH LIGHT WEIGHT HIGH REPS RESULT IN MORE FAT LOSS SUMMARY
- Training with light weight high reps training protocol resulted in similar fat loss to a heavier weight training protocol.
- Resistance exercise may increase NEAT levels, which can lead to additional calories burned throughout the day.
Resistance training can increase/preserve lean mass while dieting, whereas aerobic exercise is associated with losses in lean muscle.(1, 2) Another benefit of resistance training is that it increases NEAT compared to aerobic exercise, which has been found to reduce Non-Exercise Adaptative Thermogenesis (N.E.A.T. exercise).
NEAT MEANING AND HOW TO INCREASE NEAT
The definition of NEAT is any activity that relates to physical activity outside of exercise. For example, you run on the treadmill for an hour but are so tired after exercising that you want to sit, relax, and watch TV. The total calories you have burned throughout the day go down because you move less and burn fewer calories. In contrast, resistance exercise has the potential to increase NEAT. This was documented in a study in which differences in 24-h energy expenditure and daily physical activity levels were assessed after 16 weeks of aerobic training and resistance exercise using a randomized crossover design.
BURN MORE CALORIES WITH NEAT
Both activities resulted in an increase in 24-h energy expenditure on exercise days. On exercise days, total daily energy expenditure increased more on aerobic days by 443 kcal/d and 239 kcal/d for resistance exercise. However, on days that the subjects were not exercising was a different story. On non-exercising days, NEAT levels decreased in the aerobic group, and the subjects burned -148 kcal/day, whereas, on non-exercising days, NEAT levels increased, and subjects burned more than +216 kcal/day in the resistance exercise group.
The researchers concluded that resistance exercise may burn more calories in the long term by stimulating higher physical activity on non-exercising days. The lower fatigue and lower energy expenditure during resistance exercise may result in less time to recover between exercises and greater physical activity on non-exercise days. Thus, aerobic exercise can cause a compensatory reduction in calories by lowering calories burned on non-exercising days from greater fatigue.(3) Thus, NEAT weight loss may be greater with resistance exercise.
Several studies have found that when comparing diet alone to diet plus resistance exercise, despite weight loss being the same between groups, body composition improves favorably when diet is combined with resistance exercise (i.e., greater reductions in body fat and preservation of lean mass).(4, 5)
Is Training with Light Weights High Reps Better for Fat Loss
Most bodybuilders typically switch from lifting heavier with fewer reps to a lighter weight with more repetitions in the weeks leading to the competition. However, no studies examine whether using a lighter weight is better for fat loss than using a heavier weight. A previous study found that bench press performed to failure with a lighter weight (i.e., 37%, 46%, and 56% of a 1RM) resulted in greater calories burned (I.e., 60.2 kcals) post-exercise than training with a heavier weight (i.e., 43.2 kcals) (i.e., 70%, 80%, and 90% of a 1RM).
One flaw of the study was that the lightweight endurance group performed more total work than the heavier weight groups. of has been found to result in greater calories burned.(6) Another study found that excess post-oxygen consumption calories burned (~ 5 kcals) were slightly higher for a muscle endurance training program with three sets of lightweight performed at 30% of a 1RM compared to training with a heavier weight at 80% of a 1RM until failure.(7) Again, another shortcoming of this study was that the workloads were not equal, and the lightweight group performed more reps and total exercise.
A NEW STUDY COMPARES DIETING TRAINING WITH LIGHT WEIGHT HIGH REPS VS HEAVY WEIGHT FOR FAT LOSS
None of the studies above were conducted with subjects in a calorie-restricted state, but luckily, a new study can help shed some light on the effects of calorie restriction with heavier and lighter weights.
Using a crossover design, researchers randomly assigned participants to a 4-week supervised resistance training protocol. Participants either lifted a heavier load (HL; approximately 80% of their one-repetition maximum) or a lighter load (LL; approximately 60% of their one-repetition maximum). After the initial 4 weeks, participants took an 8-week break, returning to their prior training routines.
Subsequently, they switched to the opposite training condition. For instance, if they started with the heavier load in the first 4 weeks, they used the lighter load in weeks 13-16, and vice versa.
The entire study spanned 17 weeks. Throughout the study, participants cut their calorie intake by 20% and maintained a protein intake of 1.5 grams per kilogram of body mass, equivalent to 0.7 grams per pound of body weight.
In this study, two groups of participants continued performing repetitions until they reached the point of momentary failure (MF), where they couldn’t complete the repetition despite their best efforts. These participants, being well-trained and familiar with advanced overload principles, performed 2 forced repetitions for all exercises except the ones used for testing, such as chest press, leg press, and pull-down. When participants exceeded the predetermined upper ranges for either condition (more than 10 repetitions or over 60 seconds for the high load (HL), and beyond 20 repetitions or 120 seconds for the low load (LL)), they increased the loads by approximately 5%.
RESULTS
At the end of the study, there were no differences in fat loss or lean mass changes when training with either a heavier or lighter weight when in calorie restriction.(8) This suggests that the acute studies that have found greater changes in energy expenditure with using light weight did not translate to greater fat loss when performed over a period of weeks. These were well-trained participants, so it’s not surprising that there were little changes in lean mass or strength gains with the 4-week training protocol comprising either light or heavy weight.
Training with a heavier or lighter weight in a calorie restriction resulted in similar losses in body fat. Based on the study results, using a lighter weight with more repetitions does not seem to enhance fat loss compared to a heavier weight when using a 20% calorie-restricted diet.
TRAINING WITH LIGHT WEIGHT HIGH REPS RESULT IN MORE FAT LOSS KEY POINTS
- A similar fat loss occurred when using a lighter weight training protocol to failure and a heavier weight training protocol.
- Resistance exercise may increase NEAT levels, which can lead to additional calories burned throughout the day.
REFERENCES
6. Scott CB, Leighton BH, Ahearn KJ, McManus JJ. Aerobic, anaerobic, and excess postexercise oxygen consumption energy expenditure of muscular endurance and strength: 1-set of bench press to muscular fatigue. J Strength Cond Res. 2011;25(4):903-8.
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