In mice fed a high-fat diet, repeatedly losing and regaining weight did not change the levels of glucose, triglycerides, or free fatty acids in the blood after fasting.
See the scientific wording
In male C57BL/6J mice fed a fixed high-fat diet, repeated cycles of weight loss and regain had no effect on fasting serum glucose, triglyceride, or free fatty acid concentrations.
Correlational — new studies may shift this
Randomized trialsOne low-scoring study links this claim to the outcome, but causation is not established.
What the research says
1 study reviewedSupporting (1)
Cohort StudyAnimal2017
Mice that kept losing and gaining weight on the same high-fat food ended up with the same blood sugar and fat levels as mice that didn’t diet at all — so cycling weight didn’t mess up their metabolism.
Contradicting (0)
No contradicting studies found yet
That doesn't mean it's settled — it just means no study has tested the opposite.
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When mice eat the same high-fat food but go through cycles of eating less and then eating normally again, they end up consuming less food overall over time. This means their bodies burn more fat than they store, so their fat cells stay smaller and their fat tissue stays lighter. Because their fat tissue doesn’t grow back to normal size, the hormones and fats that come from it — like leptin, glucose, and triglycerides — stay at normal levels, even after gaining and losing weight multiple times. This is why their blood sugar and fat levels don’t get worse, even though they keep cycling weight. This pattern was seen in mice studied in 10.3390/nu9101149.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting study
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In mice fed a high-fat diet, repeatedly losing and regaining weight did not change the levels of glucose, triglycerides, or free fatty acids in the blood after fasting.
Mechanism
1 studyWhen mice cycle between eating less and eating normally on the same high-fat diet, they end up eating less overall, so their fat cells stay small and their fat tissue doesn’t grow back fully. Because their fat tissue stays smaller, the fats and sugars in their blood stay at normal levels, even after losing and gaining weight multiple times — this is shown in 10.3390/nu9101149.
When mice eat the same high-fat food but go through cycles of eating less and then eating normally again, they end up consuming less food overall over time. This means their bodies burn more fat than they store, so their fat cells stay smaller and their fat tissue stays lighter. Because their fat tissue doesn’t grow back to normal size, the hormones and fats that come from it — like leptin, glucose, and triglycerides — stay at normal levels, even after gaining and losing weight multiple times. This is why their blood sugar and fat levels don’t get worse, even though they keep cycling weight. This pattern was seen in mice studied in 10.3390/nu9101149.
Repeated cycles of calorie restriction followed by ad libitum re-feeding result in a persistent reduction in cumulative daily energy intake without altering energy expenditure or food efficiency, as measured by lower total food consumption over the experimental period in weight-cycled mice compared to controls.
Chronic lower energy intake creates a sustained negative energy balance during restriction phases, leading to mobilization of stored lipids from white adipose tissue and preventing full restoration of fat mass during re-feeding phases.
Reduced lipid accumulation in adipocytes results in smaller adipocyte size and lower mass of epididymal and perirenal white adipose tissue, without loss of lean mass.
Smaller adipose tissue mass leads to reduced secretion of leptin and other adipokines, which correlates with stable circulating levels of free fatty acids, triglycerides, and fasting glucose due to maintained adipose tissue function and insulin sensitivity.
Evidence from Studies
Supporting (1)
Community contributions welcome
Mice that kept losing and gaining weight on the same high-fat food ended up with the same blood sugar and fat levels as mice that didn’t diet at all — so cycling weight didn’t mess up their metabolism.
Contradicting (0)
Community contributions welcome
Score Breakdown
No multi-axis breakdown available yet. The overall Pro / Against score above is the best signal.
- No clinical evidence is available; the score reflects mechanistic plausibility only.
What Would Prove This
Per GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this claim, ordered from strongest to weakest.
Systematic Review of Weight Cycling Effects on Fasting Glucose and Lipids in High-Fat Diet-Fed Mice
Population: Male C57BL/6J mice on fixed high-fat diets; Intervention: Weight cycling via repeated cycles of caloric restriction and refeeding; Comparator: Stable weight maintenance on same diet; Outcomes: Fasting serum glucose, triglycerides, free fatty acids; Duration: Multiple cycles over 8–16 weeks
Randomized Controlled Trial of Weight Cycling vs Stable Weight on Fasting Metabolites in Male C57BL/6J Mice
Population: Male C57BL/6J mice on fixed high-fat diet; Intervention: Weight cycling protocol (e.g., 4 cycles of 10% weight loss followed by regain); Comparator: Stable weight group with same caloric intake; Outcomes: Fasting serum glucose, triglycerides, free fatty acids; Duration: 12 weeks with 4 cycles
Longitudinal Cohort Study of Weight Cycling and Fasting Metabolic Markers in Male C57BL/6J Mice
Population: Male C57BL/6J mice on fixed high-fat diet; Intervention: Natural or induced weight cycling over time; Comparator: None (observational); Outcomes: Serial measurements of fasting glucose, triglycerides, free fatty acids; Duration: 20+ weeks with repeated measurements
Animal Model Study of Weight Cycling Effects on Fasting Lipid and Glucose Homeostasis in Male C57BL/6J Mice
Population: Male C57BL/6J mice on fixed high-fat diet; Intervention: Weight cycling via controlled feeding regimens; Comparator: Non-cycling control group; Outcomes: Fasting serum glucose, triglycerides, free fatty acids; Duration: 8–12 weeks with 3–4 cycles
In Vitro Study of Hepatocyte Glucose and Lipid Metabolism Following Weight Cycling Serum Exposure
Population: Primary hepatocytes from male C57BL/6J mice; Intervention: Exposure to serum from weight-cycled vs. stable-weight mice; Comparator: Serum from stable-weight mice; Outcomes: Glucose output, triglyceride synthesis, fatty acid oxidation rates; Duration: 24–48 hour exposure