James Smith

University of Cape Town | UCT · Department of Human Biology

South Africa faces a dual burden of non-communicable diseases (NCDs) and communicable diseases, exacerbated by the high consumption of processed foods. The Eat Better South Africa (EBSA) program implements community-based low-carbohydrate, high-fat (LCHF) interventions to address these issues. This study evaluated the impact of EBSA's 6-week progra...

Eat Better South Africa (EBSA) is an organization that provides low-carbohydrate, high-fat (LCHF) nutrition and health education programs for women from under-resourced South African communities. Community assessments are essential to explore participants' potential facilitators and challenges of adhering to new dietary behaviours and should be imp...

Scientific evidence suggests that low-carbohydrate high-fat (LCHF) diets may be effective for managing non-communicable diseases (NCDs). Eat Better South Africa (EBSA) is an organization that runs LCHF nutrition education programs for women from low-income communities. Three focus group discussions (FGDs) were held with 18 women who had taken part...

Very little is known about how long-term (>6 months) adaptation to a low-carbohydrate, high-fat (LCHF) diet affects insulin signaling in healthy, well-trained individuals. This study compared glucose tolerance; skeletal muscle glucose transporter 4 (GLUT4) and insulin receptor substrate 1 (IRS1) content; and muscle enzyme activities representative...

Background Low carbohydrate high fat (LCHF) diets are increasing in popularity amongst patients with type 2 diabetes (T2D), however it is unclear what constitutes a sustainable LCHF diet in a real-world setting. Methods This descriptive multi-method study characterized the diets, T2D status, and personal experiences of individuals with T2D who cla...

This is a letter in response to Maunder et al. 2018 (Sports Med) in which substrate metabolism during an Ironman triathlon was modeled in relation to athlete level and nutritional strategy. We felt the fat-adaptation nutritional strategy was poorly represented and unfairly dismissed in the model.

This case study documents the performance of an elite-level, exceptionally well fat-adapted endurance athlete, as he reintroduced carbohydrate ingestion during high-intensity training. He had followed a strict low-carbohydrate high-fat (LCHF) diet for 2 years during which he ate approximately 80 g of carbohydrate per day and trained and raced while...

Exercise testing on motorised treadmills provides valuable information about running performance and metabolism; however, the impact of treadmill type on these tests has not been investigated. This study compared the energy demand of running on two laboratory treadmills: an HP Cosmos (C) and a Quinton (Q) model, with the latter having a 4.5 times s...

Key points: Blood glucose is an important fuel for endurance exercise. It can be derived from ingested carbohydrate, stored liver glycogen and newly synthesized glucose (gluconeogenesis). We hypothesized that athletes habitually following a low carbohydrate high fat (LCHF) diet would have higher rates of gluconeogenesis during exercise compared to...

Contractile activity during physical exercise induces an increase in GLUT4 expression in skeletal muscle, helping to improve glucose transport capacity and insulin sensitivity. An important mechanism by which exercise upregulates GLUT4 is through the activation of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) in response to elevated levels...

TBX3 is a member of the T-box family of genes that encode developmentally important transcription factors. Mutations resulting in decreased levels of functional TBX3 lead to Ulnar-Mammary Syndrome and increased levels of TBX3 have been linked to several cancers. To understand the mechanisms regulating TBX3 expression we have previously cloned the 5...

The role of CaMK II in regulating GLUT4 expression in response to intermittent exercise was investigated. Wistar rats completed 5 x 17-min bouts of swimming after receiving 5 mg/kg KN93 (a CaMK II inhibitor), KN92 (an analog of KN93 that does not inhibit CaMK II), or an equivalent volume of vehicle. Triceps muscles that were harvested at 0, 6, or 1...

This study was conducted to explore the mechanism by which caffeine increases GLUT4 expression in C(2)C(12) myotubes. Myoblasts were differentiated in DMEM containing 2% horse serum for 13 days and the resultant myotubes exposed to 10 mM caffeine in the presence or absence of 25 microM KN93 or 10 mM dantrolene for 2 h. After the treatment, cells we...

In vitro binding assays have indicated that the exercise-induced increase in muscle GLUT4 is preceded by increased binding of myocyte enhancer factor 2A (MEF2A) to its cis-element on the Glut4 promoter. Because in vivo binding conditions are often not adequately recreated in vitro, we measured the amount of MEF2A that was bound to the Glut4 promote...

One of the desiccation‐tolerant mechanisms of the resurrection plant, Xerophyta humilis, is the ability to shut down photosynthesis reversibly. The X. humilis psbR and ChlP genes, encoding the 10 kDa polypeptide of photosystem II (PSII) and a geranylgeranyl reducatase, respectively, were isolated in a differential display screen as dehydration‐down...