{
  "slug": "carbohydrate-insulin-obesity",
  "title": "The Carbohydrate–Insulin Model of Obesity",
  "claim": "In common human obesity, a diet high in glycemic load is the primary modifiable upstream cause: its hormonal response, centred on a raised insulin-to-glucagon ratio, shifts fuel partitioning toward adipose storage and lowers fuel availability to other tissues, which increases hunger and lowers energy expenditure, so that fat storage drives positive energy balance rather than following from it; after an adaptation period of weeks, a lower-glycemic-load diet should therefore raise energy expenditure at equal energy and protein intake and reduce ad libitum intake.",
  "update_date": "2026-10-05",
  "search_cutoff": "2026-10-05",
  "framework_for_addendum": "HSEF v5.3 causal distinctions",
  "historical_scorecard_schema": "5.4",
  "regraded": false,
  "status": "curated_local_addendum",
  "full_academic_review_complete": false,
  "summary": "Diet interventions can change insulin, expenditure and intake, but several predictions of the broad causal model fail in particular controlled settings. Adaptation, diet order, food properties and expenditure measurement remain material sources of disagreement.",
  "timeline": [
    {
      "year": "1999",
      "source_id": "P10049982",
      "design": "Acute crossover in adolescents",
      "finding": "High-glycemic-index meals increased subsequent voluntary intake in the tested setting.",
      "limit": "Acute meal effects do not establish chronic obesity initiation.",
      "historical_anchor_only": false
    },
    {
      "year": "2015",
      "source_id": "P26278052",
      "design": "Short metabolic-ward randomized crossover",
      "finding": "Fat restriction produced more calculated body-fat loss than carbohydrate restriction at matched calories.",
      "limit": "Six-day comparisons do not settle all longer adaptation predictions.",
      "historical_anchor_only": false
    },
    {
      "year": "2016",
      "source_id": "P27385608",
      "design": "Sequential isocaloric ketogenic feeding",
      "finding": "Expenditure increased modestly while body-fat loss did not accelerate.",
      "limit": "Sequence, energy imbalance and measurement precision bound inference.",
      "historical_anchor_only": false
    },
    {
      "year": "2018",
      "source_id": "P29466592",
      "design": "DIETFITS randomized trial",
      "finding": "Weight loss did not significantly differ; baseline insulin secretion did not select the better diet.",
      "limit": "Free-living diet advice does not isolate every proposed mediator.",
      "historical_anchor_only": false
    },
    {
      "year": "2018",
      "source_id": "P30429127",
      "design": "Weight-maintenance randomized feeding",
      "finding": "Lower carbohydrate intake increased reported expenditure after weight loss.",
      "limit": "Outpatient adherence and expenditure-estimation assumptions need scrutiny; correction notice retained.",
      "historical_anchor_only": false
    },
    {
      "year": "2021",
      "source_id": "P33479499",
      "design": "Ad libitum inpatient crossover",
      "finding": "The high-glycemic-load low-fat diet produced lower intake than the ketogenic comparator.",
      "limit": "Food properties and short crossover periods limit attribution to a single pathway.",
      "historical_anchor_only": false
    },
    {
      "year": "2024",
      "source_id": "P39163976",
      "design": "Secondary analyses of two crossover trials",
      "finding": "Diet order affected the macronutrient study but not the ultra-processing study.",
      "limit": "Reuses original cohorts; this is a sensitivity analysis, not an independent replication.",
      "historical_anchor_only": false
    },
    {
      "year": "2025",
      "source_id": "P40043690",
      "design": "Randomized acute glycemic-index meals",
      "finding": "Glucose/insulin responses differed, while hunger and individual intake relations gave little model support.",
      "limit": "Acute healthy-adult responses do not test weeks-long adaptation in common obesity.",
      "historical_anchor_only": false
    }
  ],
  "gaps": [
    {
      "id": "G1",
      "question": "Do adaptation and order explain conflicting intake effects?",
      "source_ids": [
        "P27385608",
        "P33479499",
        "P39163976",
        "P40043690"
      ],
      "alternative": "Carryover, gut adaptation, fibre or food mass may dominate short crossover contrasts.",
      "discriminating_test": "Longer randomized feeding with washout or parallel arms, prespecified adaptation windows and intake endpoints; match food properties.",
      "gap_type": "bounded_causal_uncertainty",
      "interpretation": "An unresolved inference or scope limit in the checked evidence, not a claim that no relevant study exists anywhere."
    },
    {
      "id": "G2",
      "question": "Is an expenditure advantage reproducible across methods?",
      "source_ids": [
        "P27385608",
        "P30429127"
      ],
      "alternative": "Doubly labelled water assumptions, energy imbalance and adherence may shift estimated effects.",
      "discriminating_test": "Concurrent chamber calorimetry, isotope methods and measured food intake; prespecify correction models, baseline and energy-balance checks.",
      "gap_type": "bounded_causal_uncertainty",
      "interpretation": "An unresolved inference or scope limit in the checked evidence, not a claim that no relevant study exists anywhere."
    },
    {
      "id": "G3",
      "question": "Does insulin–glucagon change mediate hunger or adiposity?",
      "source_ids": [
        "P10049982",
        "P26278052",
        "P40043690"
      ],
      "alternative": "Insulin may respond to intake, while sensory, intestinal or reward mechanisms affect hunger.",
      "discriminating_test": "Safe controlled mechanistic studies and longitudinal mediation within diet randomization; control glucose, protein, fibre and energy density.",
      "gap_type": "bounded_causal_uncertainty",
      "interpretation": "An unresolved inference or scope limit in the checked evidence, not a claim that no relevant study exists anywhere."
    },
    {
      "id": "G4",
      "question": "Which phenotype benefits, over what time scale?",
      "source_ids": [
        "P30429127",
        "P29466592",
        "P33479499"
      ],
      "alternative": "Weight-loss maintenance, untreated obesity and acute healthy-adult responses may have different effect modifiers.",
      "discriminating_test": "Prespecified insulin-secretion and disease-stage strata in independently replicated longer trials; compare interactions rather than post hoc responder subsets.",
      "gap_type": "bounded_causal_uncertainty",
      "interpretation": "An unresolved inference or scope limit in the checked evidence, not a claim that no relevant study exists anywhere."
    }
  ],
  "source_cards": [
    {
      "id": "P10049982",
      "pmid": "10049982",
      "doi": "10.1542/peds.103.3.e26",
      "title": "High glycemic index foods, overeating, and obesity.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/10049982/",
      "issue_year": "1999",
      "electronic_date": "",
      "access_depth": "abstract_excerpt_checked",
      "checked_details": "Primary record and selected abstract passages checked; no complete-paper appraisal credited.",
      "publication_types": [
        "Clinical Trial",
        "Controlled Clinical Trial",
        "Journal Article",
        "Research Support, Non-U.S. Gov't",
        "Research Support, U.S. Gov't, P.H.S."
      ],
      "correction_notices": [],
      "cohort_note": "No independence claim made; cohort identity beyond the cited report was not exhaustively audited.",
      "baseline_access_depth": "abstract_metadata",
      "complete_paper_examined_in_this_update": false
    },
    {
      "id": "P26278052",
      "pmid": "26278052",
      "doi": "10.1016/j.cmet.2015.07.021",
      "title": "Calorie for Calorie, Dietary Fat Restriction Results in More Body Fat Loss than Carbohydrate Restriction in People with Obesity.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/26278052/",
      "issue_year": "2015",
      "electronic_date": "2015-08-13",
      "access_depth": "abstract_excerpt_checked",
      "checked_details": "Primary record and selected abstract passages checked; no complete-paper appraisal credited.",
      "publication_types": [
        "Journal Article",
        "Research Support, N.I.H., Intramural"
      ],
      "correction_notices": [],
      "cohort_note": "No independence claim made; cohort identity beyond the cited report was not exhaustively audited.",
      "baseline_access_depth": "full_text_complete",
      "complete_paper_examined_in_this_update": false
    },
    {
      "id": "P27385608",
      "pmid": "27385608",
      "doi": "10.3945/ajcn.116.133561",
      "title": "Energy expenditure and body composition changes after an isocaloric ketogenic diet in overweight and obese men.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/27385608/",
      "issue_year": "2016",
      "electronic_date": "2016-07-06",
      "access_depth": "abstract_excerpt_checked",
      "checked_details": "Primary record and selected abstract passages checked; no complete-paper appraisal credited.",
      "publication_types": [
        "Clinical Trial",
        "Journal Article"
      ],
      "correction_notices": [],
      "cohort_note": "No independence claim made; cohort identity beyond the cited report was not exhaustively audited.",
      "baseline_access_depth": "full_text_complete",
      "complete_paper_examined_in_this_update": false
    },
    {
      "id": "P30429127",
      "pmid": "30429127",
      "doi": "10.1136/bmj.k4583",
      "title": "Effects of a low carbohydrate diet on energy expenditure during weight loss maintenance: randomized trial.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/30429127/",
      "issue_year": "2018",
      "electronic_date": "2018-11-14",
      "access_depth": "abstract_excerpt_checked",
      "checked_details": "Primary record and selected abstract passages checked; no complete-paper appraisal credited.",
      "publication_types": [
        "Journal Article",
        "Multicenter Study",
        "Randomized Controlled Trial",
        "Research Support, N.I.H., Extramural",
        "Research Support, Non-U.S. Gov't"
      ],
      "correction_notices": [
        {
          "type": "ErratumIn",
          "pmid": "33144344",
          "note": ""
        }
      ],
      "cohort_note": "No independence claim made; cohort identity beyond the cited report was not exhaustively audited.",
      "baseline_access_depth": "full_text_complete",
      "complete_paper_examined_in_this_update": false,
      "notice_check_scope": "Correction 33144344 was read: the pre-randomization column in Table 3 reports standard errors rather than standard deviations. That distinction must be retained when interpreting uncertainty."
    },
    {
      "id": "P29466592",
      "pmid": "29466592",
      "doi": "10.1001/jama.2018.0245",
      "title": "Effect of Low-Fat vs Low-Carbohydrate Diet on 12-Month Weight Loss in Overweight Adults and the Association With Genotype Pattern or Insulin Secretion: The DIETFITS Randomized Clinical Trial.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/29466592/",
      "issue_year": "2018",
      "electronic_date": "",
      "access_depth": "abstract_excerpt_checked",
      "checked_details": "Primary record and selected abstract passages checked; no complete-paper appraisal credited.",
      "publication_types": [
        "Comparative Study",
        "Journal Article",
        "Randomized Controlled Trial",
        "Research Support, N.I.H., Extramural"
      ],
      "correction_notices": [
        {
          "type": "ErratumIn",
          "pmid": "29614160",
          "note": ""
        },
        {
          "type": "ErratumIn",
          "pmid": "29710144",
          "note": ""
        }
      ],
      "cohort_note": "No independence claim made; cohort identity beyond the cited report was not exhaustively audited.",
      "baseline_access_depth": "full_text_complete",
      "complete_paper_examined_in_this_update": false,
      "notice_check_scope": "Linked notice presence was checked in the primary record; its scientific impact was not verified in this update."
    },
    {
      "id": "P33479499",
      "pmid": "33479499",
      "doi": "10.1038/s41591-020-01209-1",
      "title": "Effect of a plant-based, low-fat diet versus an animal-based, ketogenic diet on ad libitum energy intake.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/33479499/",
      "issue_year": "2021",
      "electronic_date": "2021-01-21",
      "access_depth": "abstract_excerpt_checked",
      "checked_details": "Primary record and selected abstract passages checked; no complete-paper appraisal credited.",
      "publication_types": [
        "Journal Article",
        "Randomized Controlled Trial",
        "Research Support, N.I.H., Extramural",
        "Research Support, Non-U.S. Gov't"
      ],
      "correction_notices": [],
      "cohort_note": "NCT03878108; reused in the diet-order reanalysis.",
      "baseline_access_depth": "abstract_metadata",
      "complete_paper_examined_in_this_update": false
    },
    {
      "id": "P39163976",
      "pmid": "39163976",
      "doi": "10.1016/j.ajcnut.2024.08.013",
      "title": "Diet order significantly affects energy balance for diets varying in macronutrients but not ultraprocessing in crossover studies without a washout period.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/39163976/",
      "issue_year": "2024",
      "electronic_date": "2024-08-18",
      "access_depth": "abstract_excerpt_checked",
      "checked_details": "Primary record and selected abstract passages checked; no complete-paper appraisal credited.",
      "publication_types": [
        "Journal Article",
        "Randomized Controlled Trial",
        "Research Support, N.I.H., Intramural"
      ],
      "correction_notices": [],
      "cohort_note": "Secondary analysis of NCT03878108 and NCT03407053; overlap with original diet reports.",
      "baseline_access_depth": "full_text_complete",
      "complete_paper_examined_in_this_update": false
    },
    {
      "id": "P40043690",
      "pmid": "40043690",
      "doi": "10.1016/j.cmet.2025.01.015",
      "title": "Testing the carbohydrate-insulin model: Short-term metabolic responses to consumption of meals with varying glycemic index in healthy adults.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/40043690/",
      "issue_year": "2025",
      "electronic_date": "",
      "access_depth": "abstract_excerpt_checked",
      "checked_details": "Primary record and selected abstract passages checked; no complete-paper appraisal credited.",
      "publication_types": [
        "Journal Article",
        "Randomized Controlled Trial"
      ],
      "correction_notices": [
        {
          "type": "ErratumIn",
          "pmid": "40306286",
          "note": ""
        }
      ],
      "cohort_note": "No independence claim made; cohort identity beyond the cited report was not exhaustively audited.",
      "baseline_access_depth": "abstract_metadata",
      "complete_paper_examined_in_this_update": false,
      "notice_check_scope": "Linked notice presence was checked in the primary record; its scientific impact was not verified in this update."
    }
  ],
  "access_counts": {
    "full_text_partial": 0,
    "abstract_excerpt_checked": 8,
    "metadata_only": 0
  },
  "browser_messages": 2,
  "targeted_check": {
    "pmid": "39163976",
    "provider_access": "abstract only",
    "independent_primary_body_crosscheck": false,
    "verification_scope": "The targeted Consensus answer reported abstract-only access. Primary abstract and metadata were checked; no independently readable body was verified in this update."
  },
  "editorial_warning": "Consensus attributed some milestones to later commentary or review papers. The chronology uses primary identifiers and keeps secondary cohort analyses explicit.",
  "reading_limit": "This focused addendum does not establish 50–70 complete primary Methods/Results examinations per review. Baseline reading receipts and scores retain their original scope.",
  "method": "Case-specific Consensus records assisted gap discovery, chronology and targeted paper questions. Shared template wording about an amyloid-specific Deep follow-up is not evidence of a Deep run for this topic; the dated source records establish the actual use and access limits. Primary identifiers, selected abstract passages, correction notices and available primary-body passages were cross-checked. Generated absence cells, duplicate milestones and unsupported access claims were rejected."
}