EAL

NAP: Energy Balance and Body Composition (2014)

Citation:

Garthe I, Raastad T, Sundgot-Borgen J. Long-term effect of weight loss on body composition and performance in elite athletes. Int J Sport Nutr Exerc Metab. 2011; 21: 426-435.

Study Design:

Randomized Controlled Trial

Class:

A - Click here for explanation of classification scheme.

Quality Rating:

POSITIVE: See Quality Criteria Checklist below.

Research Purpose:

To compare changes in body mass (BM), fat mass (FM), lean body mass (LBM) and performance six and 12 months after two different weight loss (WL) interventions promoting loss of 0.7% vs. 1.4% of body weight per week in elite athletes.

Inclusion Criteria:

Elite athletes ages 18 to 35 years.

Exclusion Criteria:

Diseases and conditions known to affect metabolic functions in muscle
Use of pharmaceuticals that might affect any of the measurements
Presence of one or more components of the female athlete triad
Clinically evident perimenopausal condition
Pregnancy
FM corresponding to a predicted post-intervention body-fat value of less than 5% for men and 12% for women
Anorexia nervosa, bulimia nervosa and eating disorders not otherwise specified using DSM-IV criteria.

Description of Study Protocol:

Recruitment

Invitation from the Norwegian Olympic Sport Center when they contacted the center to get assistance with weight loss or by invitation letters to sport federations.

Design

Block-randomized trial.

Intervention

Slow rate (SR) vs. fast rate (FR) weight loss (WL). The length of the intervention was determined by the rate of weight loss (SR or FR) and the desired weight loss (minimum 4% of BM) for each athlete who was given nutritional counseling once a week during intervention. Diet plan to provide 1.2g to 1.8g per kg protein, 4g to 6g per kg CHO and 20% or fat daily, with low-energy, high-nutrient-density foods that provided satiety
Diet plans included five to seven meals and snacks daily. No meal plan was less than 1,500kcals. All athletes ingested a milk protein-based recovery meal containing CHO (2g to 40g) and PRO (6g to 20g) within 30 minutes of each training session, and a balanced meal within one to two hours to optimize recovery. After intervention, the athletes received one nutrition counseling session within four weeks and exercise counseling to stabilize the new BM and body composition.

Statistical Analysis

Changes from baseline to post-intervention and six-month and 12-month follow-up were analyzed with repeated measures ANOVAs within groups and two-way repeated-measures ANOVAs between groups. Significant interactions were corrected with Boniferroni's post-hoc test.

Data Collection Summary:

Timing of Measurements

Baseline, six months and 12 months after intervention. EDI-2 was also done at end of intervention.

Dependent Variables

Body mass (BM): Fasted state on calibrated scale
Body composition: FM and LBM in fasted state using DEXA with a trained technician
Performance:
- A 40m sprint
- Counter-movement jump
- 1RM bench press
- Bench-pull
- Squat.
EDI-2: Self-report measure with 91 items, a six-point forced-choice inventory assessing behavioral and psychological patterns common in eating disorders.

Independent Variables

SR vs. FR weight loss.

Control Variables

Milk protein-based recovery meal containing 20g to 40g CHO and 6g to 20g protein within 30 minutes of each training session and a balanced meal within one to two hours to optimize recovery. All were given a multi-vitamin and cod-liver oil supplement. If blood samples indicated any micronutrient need, the athlete was given that vitamin and blood levels were monitored. All athletes continued their sport-specific training schedule and included four strength-training sessions per week.

Description of Actual Data Sample:

Initial N: 36
Attrition (final N): 23 (nine males, 14 females).

Age

SR males: 24.9±3.5 years
SR females: 22.5±3.1 years
FR males: 19.2±1.3 years
FR females: 19.6 ± 7.9 years.

Other Relevant Demographics

No significant differences between groups for experience as an athlete, training per week or strength training in the last season.

Anthropometrics

BM:
- SR males: 78.5±14.1kg
- SR females: 69.6±7.0kg
- FR males: 79.6±15.2kg
- FR females: 66.1±22.4 kg.
%BF:
- SR males: 17±5%
- SR females: 29±7%
- FR males: 16±7%
- FR females: 29±5%.
No significant differences between groups for BM, FM, LBM or total body fat percent.

Location

Oslo, Norway.

Summary of Results:

Findings

History of dieting and weight cycling was reported by 57% of the athletes in SR and 67% of those in FR
The mean time spent in intervention for SR and FR was 8.7±2.3 weeks and 5.9±1.1 weeks, respectively
Energy intake was reduced by 31±5% in FR and 19±5% in SR during the intervention. Maintenance diet plans were reportedly followed for six months by two in SR group and five in FR group. Eight SR and four FR partially followed a diet plan and four SR and no FR followed no diet plan. At 12 months, two SR and four FR followed a maintenance diet plan for the previous six months, seven and four, respectively partly following, and five and one not following any plan.
BM was reduced by 5.8±0.7% in SR (P<0.001) and 5.7±0.9% in FR (P<0.001) during the intervention. The average weekly rates of weight loss for SR and FR were 0.7±0.4% and 1.0±0.4%, respectively. The rate of weight loss in FR was significantly higher than in SR (P<0.02). Six months after intervention SR had regained 77% of the lost BM, while FR had regained 14% (P<0.05). Twelve months after intervention, both groups had returned to their original weight.
While FM tended to decrease more in SR than in FR during the intervention (P<0.06), SR regained 90% of the FM after six months and significantly more than FR (P<0.05). Both groups had regained to their original FM after 12 months.
Total LBM increased by 2.0±0.4% in SR (P<0.001) during intervention but returned to baseline after six and 12 months. LBM did not change significantly in FR during intervention or after six or 12 months. There was no significant difference in total LBM between groups at any time.
Because of small sample size, the analysis of jumping performance and 40m sprint were excluded. There were no statistically significant changes in performance in any of the variables in FR at any time. 1RM squat improved by 15.6±7.5% (P<0.07), but was back to baseline six and 12 months after intervention. Bench-press performance increased by 17.0±2.6% (P<0.01) in SR during intervention and was still higher than baseline 12 months later (17.7±6.0%, P=0.01). There was no significant change in bench-pull performance, and there were no significant differences between groups at time point.
Women tended to gain LBM (2.0±1.8, P=0.06), while men's LBM was unchanged during the intervention (-2.0±1.0), with a significant difference between genders (P=0.03). Women had significant improvements in all 1RM parameters, while they were unchanged for men. No other significant gender differences were observed.
Not enough athletes in FR completed EDI to make a comparison. There were no significant differences in total EDI score for SR at any time.

Author Conclusion:

There were no significant differences between groups after 12 months, suggesting that weight loss rate is not the most important factor in maintaining body composition and performance after weight loss in elite athletes
The authors recommend that athletes who would like to lose 5% to 6% of BM combine moderate energy restriction with strength training to achieve gains in LBM and improvements in strength.

Funding Source:

Not-for-profit

Norwegian Olympic Sports Center

Other:

Norwegian School of Sport Sciences

Reviewer Comments:

Quality Criteria Checklist: Primary Research
Relevance Questions
	1.	Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies)	Yes
	2.	Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about?	Yes
	3.	Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice?	Yes
	4.	Is the intervention or procedure feasible? (NA for some epidemiological studies)	Yes

Validity Questions
1.	Was the research question clearly stated?		Yes
	1.1.	Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified?	Yes
	1.2.	Was (were) the outcome(s) [dependent variable(s)] clearly indicated?	Yes
	1.3.	Were the target population and setting specified?	Yes
2.	Was the selection of study subjects/patients free from bias?		Yes
	2.1.	Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study?	Yes
	2.2.	Were criteria applied equally to all study groups?	Yes
	2.3.	Were health, demographics, and other characteristics of subjects described?	Yes
	2.4.	Were the subjects/patients a representative sample of the relevant population?	Yes
3.	Were study groups comparable?		Yes
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	No
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	Yes
	3.3.	Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.)	Yes
	3.4.	If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis?	N/A
	3.5.	If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.)	N/A
	3.6.	If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")?	N/A
4.	Was method of handling withdrawals described?		Yes
	4.1.	Were follow-up methods described and the same for all groups?	Yes
	4.2.	Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.)	Yes
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	Yes
	4.4.	Were reasons for withdrawals similar across groups?	No
	4.5.	If diagnostic test, was decision to perform reference test not dependent on results of test under study?	N/A
5.	Was blinding used to prevent introduction of bias?		No
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	No
	5.2.	Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.)	No
	5.3.	In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded?	N/A
	5.4.	In case control study, was case definition explicit and case ascertainment not influenced by exposure status?	N/A
	5.5.	In diagnostic study, were test results blinded to patient history and other test results?	N/A
6.	Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described?		Yes
	6.1.	In RCT or other intervention trial, were protocols described for all regimens studied?	Yes
	6.2.	In observational study, were interventions, study settings, and clinicians/provider described?	N/A
	6.3.	Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect?	Yes
	6.4.	Was the amount of exposure and, if relevant, subject/patient compliance measured?	Yes
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	N/A
	6.6.	Were extra or unplanned treatments described?	N/A
	6.7.	Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups?	N/A
	6.8.	In diagnostic study, were details of test administration and replication sufficient?	N/A
7.	Were outcomes clearly defined and the measurements valid and reliable?		Yes
	7.1.	Were primary and secondary endpoints described and relevant to the question?	Yes
	7.2.	Were nutrition measures appropriate to question and outcomes of concern?	Yes
	7.3.	Was the period of follow-up long enough for important outcome(s) to occur?	Yes
	7.4.	Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures?	Yes
	7.5.	Was the measurement of effect at an appropriate level of precision?	Yes
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	N/A
	7.7.	Were the measurements conducted consistently across groups?	Yes
8.	Was the statistical analysis appropriate for the study design and type of outcome indicators?		Yes
	8.1.	Were statistical analyses adequately described and the results reported appropriately?	Yes
	8.2.	Were correct statistical tests used and assumptions of test not violated?	Yes
	8.3.	Were statistics reported with levels of significance and/or confidence intervals?	Yes
	8.4.	Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)?	N/A
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	N/A
	8.6.	Was clinical significance as well as statistical significance reported?	Yes
	8.7.	If negative findings, was a power calculation reported to address type 2 error?	N/A
9.	Are conclusions supported by results with biases and limitations taken into consideration?		Yes
	9.1.	Is there a discussion of findings?	Yes
	9.2.	Are biases and study limitations identified and discussed?	Yes
10.	Is bias due to study's funding or sponsorship unlikely?		Yes
	10.1.	Were sources of funding and investigators' affiliations described?	Yes
	10.2.	Was the study free from apparent conflict of interest?	Yes