Study analysis · Journal of the Medical Sciences (Berkala Ilmu Kedokteran) · 2019
Eating sweet potato and pumpkin snacks to boost resistant starch might actually increase belly fat while lowering the hunger hormone—what's going on?
A small study found that eating a snack made from tubers and pumpkin twice daily for a month lowered the hunger hormone leptin but increased visceral fat in people with type 2 diabetes, without changing their weight.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
In simple terms
This study is like trying a new snack on a group of people and seeing what happens, but without flipping a coin to decide who gets it first or who gets a fake snack. So we can see things like lower leptin levels, but we can't be sure it’s because of the snack – it could be something else.
What’s the bottom line?
Adults with type 2 diabetes ate a snack made from mixed tubers and pumpkin twice a day for 4 weeks. This snack contains resistant starch, a type of fiber that might affect blood sugar and fat. The study measured belly fat, a hunger hormone called leptin, blood sugar, and weight.
How strong is this study?
The study only had 16 people, and the order was not random. It's like a small test with a few people, so the results might not be strong. We should trust it just a little, not a lot, and wait for bigger, better-designed studies.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
33 / 100
- Randomizationnot randomized
- Blindingblinding unclear
- Control group+15/15
- Sample size (n=16)+1.5/20
- Follow-up+10/10
100 / 100
23 / 100
- P-values+15/15
- Effect sizeno effect size reported
- Confidence intervalsno confidence intervals
- Pre-registrationnot pre-registered
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 530 / 100
Probability of being correct
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
This design cannot establish causation — the findings describe an association, not a cause. This is a non-randomized crossover trial without a randomized sequence, so causal inference is limited by potential confounding, carryover effects, and lack of blinding. The observed associations could be due to unmeasured factors or time trends.
No Conflicts
No conflicts of interest identified
No conflicts of interest declared; study appears independently conducted with no industry funding.
No COI section or funding disclosure found in the provided text. The study appears to be academically conducted without external financial support.
Key takeaways
- 01
After 4 weeks, the snack lowered the hunger hormone leptin (from about 7.94 to 6.71 ng/mL, a significant drop).
- 02
But it increased belly fat (visceral fat rating went up) without changing weight.
- 03
Blood sugar did not improve with the snack; it only improved during the control period when they didn't eat the snack.
- 04
For a person, the decrease in leptin might mean less appetite control, and the increase in belly fat is unhealthy because it raises heart disease risk.
- 05
But the snack was low in resistant starch (only 4.25g per day, below the recommended dose), so effects might be different with a higher dose.
Surprising findings
- Visceral fat increased significantly after consuming a resistant-starch-rich snack for 4 weeks, contrary to the hypothesis that it would decrease.Previous animal studies suggested resistant starch reduces fat storage in adipocytes, but this human study shows the opposite for visceral fat.
- Leptin levels decreased, which is often viewed as a positive outcome, but the increase in visceral fat complicates the picture.Leptin is secreted by adipocytes, and lower levels usually indicate reduced fat mass, but here fat mass increased in the visceral depot.
- The control period (without the snack) showed a significant decrease in fasting blood glucose, but the snack period did not.It is counterintuitive that a supposedly beneficial dietary intervention had no effect on glucose, while the control period (just time passing) did.
Practical takeaways
Be cautious about consuming large amounts of resistant starch snacks, especially if you have type 2 diabetes, until more research is conducted.
This study is low quality (small sample, short duration, low dose), so findings are not definitive.
low confidenceMonitor your body composition, not just weight, to detect changes in visceral fat.
Visceral fat measurement might not be readily available; consider waist circumference as a proxy.
medium confidenceIf you're considering resistant starch for blood sugar control, ensure you get an adequate dose (at least 6g per meal) and use it as part of a comprehensive plan.
The study used 4.25g per day, which is below recommended levels, and might explain the lack of effect on glucose.
low confidenceWhy this study matters
The surprising belly fat increase
In this crossover trial, 16 adults with type 2 diabetes ate a mixed tubers and pumpkin snack (32g/day) for 4 weeks. Visceral fat significantly increased (p=0.04) in the snack period, while it decreased during the control period (p=0.04). The increase was more pronounced in females, with a between-group difference of p=0.05.
Most people assume that resistant starch, a type of fiber, is beneficial for metabolic health. Seeing it potentially increase visceral fat—a dangerous type of fat—is counterintuitive and alarming.
Leptin levels dropped significantly
Plasma leptin levels decreased from 7.94 to 6.71 ng/mL after 4 weeks of snack consumption (p=0.00), with the entire group showing a significant drop. This effect was more pronounced in females (p=0.045).
Leptin is a hormone that regulates appetite; lower levels might signal a reduction in satiety, potentially leading to increased hunger. This contradicts the expectation that resistant starch improves satiety.
No benefit for blood sugar control
Fasting blood glucose did not significantly decrease during the snack period (p=0.30), but it did decrease significantly during the control period (p=0.01). This suggests the snack did not help with glycemic control, possibly due to the low dose of resistant starch (4.25g/day, below the recommended 6g/meal).
Resistant starch is often promoted for blood sugar management, but this study failed to show improvement—potentially due to insufficient dosage or short duration.
BMI unchanged despite fat redistribution
BMI remained unchanged after the intervention (p=0.92), yet visceral fat increased. This suggests a redistribution of fat rather than overall weight gain, which is particularly concerning because visceral fat is linked to cardiovascular risk.
People often rely on scale weight as a health metric, but this study highlights that even without weight change, metabolic health can worsen.
Want the whole report?
Detailed mode opens the full scientific breakdown — every score component, the methodology, conflicts of interest, the evidence analysis behind each claim, and the raw study data.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Adults with type 2 diabetes ate a snack made from mixed tubers and pumpkin twice a day for 4 weeks. This snack contains resistant starch, a type of fiber that might affect blood sugar and fat. The study measured belly fat, a hunger hormone called leptin, blood sugar, and weight.
Research results
After 4 weeks, the snack lowered the hunger hormone leptin (from about 7.94 to 6.71 ng/mL, a significant drop). But it increased belly fat (visceral fat rating went up) without changing weight. Blood sugar did not improve with the snack; it only improved during the control period when they didn't eat the snack.
What this means - more context
For a person, the decrease in leptin might mean less appetite control, and the increase in belly fat is unhealthy because it raises heart disease risk. But the snack was low in resistant starch (only 4.25g per day, below the recommended dose), so effects might be different with a higher dose.
Determine the effectiveness of a snack made from mixed tubers and pumpkin on BMI, visceral fat, glucose, and leptin levels in T2DM patients, and examine correlations between these variables.
In a pre-post crossover trial, 16 T2DM patients consumed a mixed tubers and pumpkin snack twice daily for 4 weeks. The snack significantly decreased plasma leptin levels (p=0.00) and increased visceral fat (p=0.04), while BMI remained unchanged. Fasting blood glucose did not significantly decrease in the intervention group (p=0.30), but did decrease in the control period (p=0.01). BMI showed strong positive correlations with visceral fat. The authors conclude that the snack lowered leptin but increased visceral fat.
Methods Used
Pre-post crossover clinical trial with 16 T2DM patients (7 male, 9 female; mean age 52.75±2.24 years, mean BMI 28.23±3.39 kg/m²). Patients received a mixed tubers and pumpkin snack (32g/day, containing 4.25g resistant starch) for 4 weeks, followed by a 4-week washout, then served as their own controls. Measurements included BMI, visceral fat by bioelectrical impedance, fasting plasma glucose, and plasma leptin. Statistical analyses used paired t-test or Wilcoxon test and Pearson correlations.
Main Finding
The snack significantly decreased plasma leptin levels (p=0.00) and increased visceral fat (p=0.04) without changing BMI. Glucose did not significantly decrease in the intervention group (p=0.30) but did in the control period (p=0.01). BMI strongly correlated with visceral fat (r=0.79 in RS group, r=0.746 in control group).
Confidence Level
Low
Study Flags
Red Flags
- •Small sample size (n=16)
- •No randomization or blinding
- •Short duration (4 weeks) and resistant starch dose below recommended levels
Surprising Findings
Visceral fat increased significantly after consuming a resistant-starch-rich snack for 4 weeks, contrary to the hypothesis that it would decrease.
Previous animal studies suggested resistant starch reduces fat storage in adipocytes, but this human study shows the opposite for visceral fat.
Practical Takeaways
Be cautious about consuming large amounts of resistant starch snacks, especially if you have type 2 diabetes, until more research is conducted.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 530 / 100
Probability of being correct
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Human Case Report
Subject
Lower probability
on the GRADE evidence scale
This study is like trying a new snack on a group of people and seeing what happens, but without flipping a coin to decide who gets it first or who gets a fake snack. So we can see things like lower leptin levels, but we can't be sure it’s because of the snack – it could be something else.
The study has a COI section but no disclosure was found. A small penalty has been applied.
Strengths
- Crossover design with each subject as own control
- Use of standard measurement techniques (BIA, ELISA)
- Baseline comparability of most variables except glucose
Weaknesses
- No randomization of sequence order
- No blinding of participants or assessors
- Small sample size
Methodology
Evidence Keywords
Statistical Reporting
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Adults with type 2 diabetes ate a snack made from mixed tubers and pumpkin twice a day for 4 weeks. This snack contains resistant starch, a type of fiber that might affect blood sugar and fat. The study measured belly fat, a hunger hormone called leptin, blood sugar, and weight.
Research results
After 4 weeks, the snack lowered the hunger hormone leptin (from about 7.94 to 6.71 ng/mL, a significant drop). But it increased belly fat (visceral fat rating went up) without changing weight. Blood sugar did not improve with the snack; it only improved during the control period when they didn't eat the snack.
What this means - more context
For a person, the decrease in leptin might mean less appetite control, and the increase in belly fat is unhealthy because it raises heart disease risk. But the snack was low in resistant starch (only 4.25g per day, below the recommended dose), so effects might be different with a higher dose.
Determine the effectiveness of a snack made from mixed tubers and pumpkin on BMI, visceral fat, glucose, and leptin levels in T2DM patients, and examine correlations between these variables.
In a pre-post crossover trial, 16 T2DM patients consumed a mixed tubers and pumpkin snack twice daily for 4 weeks. The snack significantly decreased plasma leptin levels (p=0.00) and increased visceral fat (p=0.04), while BMI remained unchanged. Fasting blood glucose did not significantly decrease in the intervention group (p=0.30), but did decrease in the control period (p=0.01). BMI showed strong positive correlations with visceral fat. The authors conclude that the snack lowered leptin but increased visceral fat.
Methods Used
Pre-post crossover clinical trial with 16 T2DM patients (7 male, 9 female; mean age 52.75±2.24 years, mean BMI 28.23±3.39 kg/m²). Patients received a mixed tubers and pumpkin snack (32g/day, containing 4.25g resistant starch) for 4 weeks, followed by a 4-week washout, then served as their own controls. Measurements included BMI, visceral fat by bioelectrical impedance, fasting plasma glucose, and plasma leptin. Statistical analyses used paired t-test or Wilcoxon test and Pearson correlations.
Main Finding
The snack significantly decreased plasma leptin levels (p=0.00) and increased visceral fat (p=0.04) without changing BMI. Glucose did not significantly decrease in the intervention group (p=0.30) but did in the control period (p=0.01). BMI strongly correlated with visceral fat (r=0.79 in RS group, r=0.746 in control group).
Confidence Level
Low
Study Flags
Red Flags
- •Small sample size (n=16)
- •No randomization or blinding
- •Short duration (4 weeks) and resistant starch dose below recommended levels
Surprising Findings
Visceral fat increased significantly after consuming a resistant-starch-rich snack for 4 weeks, contrary to the hypothesis that it would decrease.
Previous animal studies suggested resistant starch reduces fat storage in adipocytes, but this human study shows the opposite for visceral fat.
Practical Takeaways
Be cautious about consuming large amounts of resistant starch snacks, especially if you have type 2 diabetes, until more research is conducted.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 530 / 100
Probability of being correct
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Human Case Report
Subject
Lower probability
on the GRADE evidence scale
This study is like trying a new snack on a group of people and seeing what happens, but without flipping a coin to decide who gets it first or who gets a fake snack. So we can see things like lower leptin levels, but we can't be sure it’s because of the snack – it could be something else.
The study has a COI section but no disclosure was found. A small penalty has been applied.
Strengths
- Crossover design with each subject as own control
- Use of standard measurement techniques (BIA, ELISA)
- Baseline comparability of most variables except glucose
Weaknesses
- No randomization of sequence order
- No blinding of participants or assessors
- Small sample size
Methodology
Evidence Keywords
Statistical Reporting
Scoring
How strong is this study?
The study only had 16 people, and the order was not random. It's like a small test with a few people, so the results might not be strong. We should trust it just a little, not a lot, and wait for bigger, better-designed studies.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
33 / 100
- Randomizationnot randomized
- Blindingblinding unclear
- Control group+15/15
- Sample size (n=16)+1.5/20
- Follow-up+10/10
100 / 100
23 / 100
- P-values+15/15
- Effect sizeno effect size reported
- Confidence intervalsno confidence intervals
- Pre-registrationnot pre-registered
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 530 / 100
Probability of being correct
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
This design cannot establish causation — the findings describe an association, not a cause. This is a non-randomized crossover trial without a randomized sequence, so causal inference is limited by potential confounding, carryover effects, and lack of blinding. The observed associations could be due to unmeasured factors or time trends.
No Conflicts
No conflicts of interest identified
No conflicts of interest declared; study appears independently conducted with no industry funding.
No COI section or funding disclosure found in the provided text. The study appears to be academically conducted without external financial support.
Standing
Who’s using this study?
The videos and claims on this site that lean on this study, and the researchers who wrote it.
1 video from Physionic cite this study, drawing 1 claim from it.
- Conflicting evidence
Evidence points in both directions — no clear conclusion yet.
Evidence