Background: Weight loss is the first-line intervention in individuals with obesity complicated by the metabolic syndrome. The large cohort Diabetes Prevention Program and Look AHEAD study have reported that weight cycling after weight loss is common and negates the metabolic benefits of weight loss.
Aim: To study the metabolic consequences of weight cycling in a cohort of adult men and women (n=54, 28 men) studied at the Clinical Research Facility at the Garvan Institute of Medical Research (Sydney).
Methods: Dual-energy X-ray absorptiometry was used to evaluate body fat, android and gynoid fat distribution and proton magnetic resonance spectroscopy to evaluate liver fat. Fasting glucose, insulin and serum lipid profile were measured, and a modified Dieting and Weight History Questionnaire1 was used to study weight and dieting throughout life.
Results: Average BMI (±SEM) was 28.6±0.8. 76% (n=41) had BMI>25 kg/m2 (Chi-squared P=0.02). All individuals in the latter category who dieted had weight cycled. The group of individuals with BMI>25 kg/m2 were classified as non-dieters (control, n=13) or dieters (n=28). The dieters were further classified as modest or severe weight cyclers (self-reported weight changes 2.5-9.0 or >9.0 kg per cycle, respectively). The control, modest and severe weight cyclers were of similar age, BMI, android and gynoid fat, and lipid profile (Table). The modest weight cyclers were the most insulin-resistant (as measured by HOMA-IR, Table). Modest weight cyclers had higher systolic blood pressure compared with the severe weight cyclers (Table). Liver fat was elevated in the modest weight cyclers compared with the control, but not different from the severe weight cycler group (Table).
Conclusion: Weight cycling may result in unfavourable effects on insulin resistance and liver fat. Modest weight cycling may be more deleterious to metabolic health than severe weight cycling.
Table: Body fat distribution and metabolic health markers in non-dieters and weight cyclers
|
Non-Dieters |
Dieters |
ANOVA P |
Posthoc P |
||||
|
Control (1) |
Modest weight cyclers (2) |
Severe weight cyclers (3) |
1 vs 2 |
1 vs 3 |
2 vs 3 |
||
|
N |
13 |
17 |
11 |
||||
|
Age (years) |
61 ± 1 |
62 ± 1 |
55 ± 1 |
0.3 |
|||
|
BMI (kg/m2) |
28.9 ± 1.0 |
31.0 ± 1.2 |
31.6 ± 1.7 |
0.4 |
|
|
|
|
Android fat (kg) |
7.0 ± 0.4 |
7.0 ± 0.4 |
7.0 ± 1.0 |
0.8 |
|
|
|
|
Gynoid fat (kg) |
13.0 ± 0.5 |
13.0 ± 0.6 |
14.0 ± 1.5 |
0.8 |
|
|
|
|
Total cholesterol (mmol/L) |
5.2 ± 0.3 |
4.4 ± 0.3 |
4.7 ± 0.4 |
0.1 |
|
|
|
|
Triglycerides (mmol/L) |
1.7 ± 0.3 |
1.6 ± 0.1 |
1.3 ± 0.3 |
0.4 |
|
|
|
|
HDL-cholesterol (mmol/L) |
1.3 ± 0.1 |
1.2 ± 0.1 |
1.4 ± 0.1 |
0.1 |
|
|
|
|
LDL-cholesterol (mmol/L) |
3.1 ± 0.2 |
2.5 ± 0.2 |
2.7 ± 0.3 |
0.1 |
|
|
|
|
Systolic blood pressure (mmHg) |
137 ± 5 |
142 ± 3 |
122 ± 5 |
0.01 |
0.8 |
0.09 |
0.01 |
|
Diastolic blood pressure (mmHg) |
85 ± 3 |
89 ± 3 |
81 ± 3 |
0.1 |
|
|
|
|
HOMA-IR |
3.4 ± 0.6 |
5.6 ± 0.7 |
3.0 ± 0.6 |
0.01 |
0.04 |
1.0 |
0.02 |
|
Liver fat (%) |
3.3 ± 0.7 |
12.4 ± 3.4 |
3.9 ± 1.9 |
0.02 |
0.02 |
1.0 |
0.12 |
Data are mean ± SEM. Overall ANOVA P are provided with posthoc analyses (Sidak), P<0.05 in bold. Android and gynoid fat data are available for n = 32, serum lipid profile for n=39 and liver fat for n = 29.
Abbreviations: HDL, high-density lipoprotein; LDL, low-density lipoprotein; HOMA-IR, homeostatic model assessment of insulin resistance.