Abstract
Background: Glycaemic control in type 2 diabetes (T2DM) deteriorates progressively over time. Diet is a cornerstone of T2DM management. It is unknown if dietary patterns impact glycaemia independent of weight change or if they impact rates of long-term glycaemic deterioration. Also unknown is whether short- and long-term dietary pattern changes differ between men and women following non-prescriptive dietetic advice.Methods: In people recently-diagnosed with T2DM, a ‘carb/fat balance’ dietary pattern and an ‘obesogenic’ dietary pattern were derived using reduced-rank regression, based on hypothesised nutrient-mediated pathways linking diet with glycaemia directly or indirectly via bodyweight. Study 1 explored weight-independent associations between changes in dietary patterns and changes in glycaemic control during a 12-month non-prescriptive dietary intervention. Study 2 explored whether differences existed between men and women in short- and long-term ‘obesogenic’ dietary pattern change during (<12 months) or following this dietary intervention (1-6 years). Study 3 explored associations between ‘carb/fat balance’ dietary patterns and the rate of glycaemic deterioration during the 5-year follow-up. Study 4 replicated analyses from study 3 in a larger, more diverse, purely observational cohort.
Results: Increases in standardised ‘carb/fat balance’ dietary pattern scores, shifting total intakes of carbohydrates higher and fats lower, associated with short-term reductions in HbA1c independent of weight loss (β=-1.54 [95%CI: -2.96, -0.13] mmol/mol/SD). No associations were found linking this dietary pattern to rates of long-term glycaemic deterioration. Study 2 found no differences in how dietary patterns change between men and women over the short- or long-term following typical non-prescriptive dietetic advice.
Conclusions: Dietary interventions in T2DM require no further tailoring to sex. Dietary patterns moving carbohydrate and fat intakes closer to meeting UK healthy eating guidelines provide small, short-term, weight loss-independent benefits to glycaemic control. Dietary patterns do not impact glycaemic progression over the long-term. Weight loss should remain the primary focus of T2DM dietary management.
| Date of Award | 24 Jan 2023 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Clare Y England (Supervisor), Ruth E Salway (Supervisor), Laura Johnson (Supervisor), Rob Andrews (Supervisor) & Angus Jones (Supervisor) |