Effects of time-restricted feeding on body weight, body composition and vital signs in low-income women with obesity: A 12-month randomized clinical trial.

BACKGROUND & AIMS: Time-restricted feeding (TRF) studies usually are of short-term, involving heterogeneous populations, without a control group with similar energy restriction. Besides, it seldom assess vital signs such as body temperature and heart rate, which may be influenced by the fasting state. In this investigation, we assessed the long-term effects of TRF on body weight, body composition and vital signs of low-income women with obesity undergoing diets with the same energy deficit. METHODS: Low-income women with obesity were randomly allocated to a group with a hypoenergetic diet and 12 h of TRF or to a group with only a hypoenergetic diet, for 12 months. Body fat and waist circumference were estimated using a tetrapolar electrical bioimpedance and an inelastic measuring tape, respectively, at baseline and after 4, 6 and 12 months of intervention. Systolic and diastolic blood pressure, heart rate, and axillary temperature were measured at baseline and 12 months of intervention. The energy content of the diets was determined based on the women's resting metabolic rate (by indirect calorimetry) and level of physical activity (by triaxial accelerometers). Effects were analyzed using an intention-to-treat approach. RESULTS: Fifty-eight women were randomized and 31 (53.44%) were lost to follow-up at 12 months. Dropout rates were similar between groups. In the intention-to-treat analysis, there were no significant changes in the body weight after 12 months (Differences in changes from baseline between groups: -0.05 95%CI [-2.34; 2.24] Kg; p = 0.96). An increase in axillary temperature (0.40 °C, 95% CI [-0.14; 0.67]°C, p < 0.01), a reduction in the percentage of body fat (-1.64%, 95% CI [-3.08; -0.19]%, p = 0.02) and waist circumference (-2.57 cm, 95% CI [-5.73; 0.58] cm, p = 0.03 in the mixed model involving 4 measurements) were observed in the intervention group, when compared to the control group. CONCLUSIONS: TRF showed no effects on weight loss. Nevertheless the findings on waist circumference and body fat, although not clinically meaningful, suggest that this strategy may help in the long-term management of obesity in this population, since it is an easy to apply intervention. Axillary temperature findings warrants further investigation. Registered under www.ensaiosclinicos.gov.br Identifier no. RBR-387v6v. TRIAL REGISTRATION: http://www.ensaiosclinicos.gov.br/rg/RBR-387v6v/.

HEPATIC FATTY ACID PROFILE OF RATS FED A TRIHEPTANOIN-BASED KETOGENIC DIET.

OBJECTIVE: the aim of this study was to evaluate the influence of consumption of a ketogenic diet supplemented with triheptanoin, a medium-chain anaplerotic triacylglycerol, on the liver fatty acid profile of Wistar rats. METHODS: three groups of male Wistar rats (n = 10) were submitted to an AIN-93 control diet, a triheptanoin- based ketogenic diet, or a soybean oil-based ketogenic diet for 60 days. Excised livers were subjected to lipid extraction and methylation to obtain fatty acids methyl esters, which were subjected to gas chromatography- mass spectrometry. RESULTS AND DISCUSSION: compared to the rats fed the control diet, those fed ketogenic diets showed a significant reduction in the concentrations of 9-hexadecenoic and 9-octadecenoic acids, whereas those fed triheptanoin showed increased levels of octadecanoic acid. CONCLUSION: changes in the liver fatty acid profiles of the rats fed a triheptanoin-based or a soybean oil-based ketogenic diet did not seem to be related to the dietary fat source, but rather to the characteristics of the ketogenic diets themselves.

Objetivo: el objetivo de este estudio fue evaluar la influencia del consumo de una dieta cetogénica complementada con triheptanoína, un triacilglicerol de cadena media y anaplerótico, en el perfil de ácidos grasos del hígado de ratones Wistar. Métodos: tres grupos de ratones Wistar machos (n = 10) fueron sometidos durante 60 días a una dieta AIN-93 de control, una dieta cetogénica basada en triheptanoína o una dieta cetogénica a base de aceite de soja. Los hígados fueron escindidos y sometidos a extracción de lípidos y metilación para obtener los ésteres metílicos de ácidos grasos, que se sometieron a cromatografía de gas-espectrometría de masa. Resultados y discusión: en comparación con los ratones alimentados con la dieta de control, los de ambas dietas cetogénicas mostraron una reducción significativa en las concentraciones de los ácidos grasos 9-hexadecenoico y 9-octadecenoico, mientras que los alimentados con triheptanoína mostraron niveles de ácido octadecenoico aumentados. Conclusión: los cambios en los perfiles de ácidos grasos del hígado de los ratones alimentados con dietas cetogénicas no están relacionados con la fuente de grasa de la dieta (triheptanoína o aceite de soja), sino más bien con la concentración total de lípidos.