Efficacy and safety of long-term low-calorie diet in severely obese patients non-eligible for surgery

The Real-Life Use of a Protein-Sparing Modified Fast Diet by Nasogastric Tube (ProMoFasT) in Adults with Obesity: An Open-Label Randomized Controlled Trial

BACKGROUND

Protein-sparing modified fast (PSMF) diet is a very-low-carbohydrate ketogenic diet administered to patients with obesity, which preserves lean mass and suppresses appetite as well as continuous enteral feeding. Thus, we aim to evaluate the effect of the PSMF diet administered continuously by nasogastric tube (NGT) or orally.

METHODS

Patients with a body mass index (BMI) > 34.9 kg/m2 were randomly assigned to receive a whey protein PSMF formula through NGT (ProMoFasT) or orally. Data were collected at baseline and after 150 days. The endpoints were assessed in the intention-to-treat population.

RESULTS

We enrolled 20 patients in the ProMoFasT group and 24 in the oral group. No differences in body weight, BMI or waist circumference between the two groups were found after 150 days. At follow-up, FFM (%) and MM (%) results were higher in the ProMoFasT group than the oral group (63.1% vs. 52.9%, p = 0.012 and 45.0% vs. 36.1%, p = 0.009, respectively) and FM (kg) and FM (%) were significantly lower in the ProMoFasT group (36.9 kg vs. 44.0 kg, p = 0.033 and 37.4% vs. 44.9%, p = 0.012, respectively). Insulin levels were lower in the ProMoFasT group than the oral group at follow-up (11.8 mU/L vs. 28.0 mU/L, p = 0.001, respectively).

CONCLUSION

The ProMoFasT is more effective in improving body composition and glucometabolic markers than the same diet administered orally.

Effectiveness and Characterization of Severely Energy-Restricted Diets in People with Class III Obesity: Systematic Review and Meta-Analysis

Severely energy-restricted diets are used in obesity management, but their efficacy in people with class III obesity (body mass index ≥40 kg/m2) is uncertain. The aims of this systematic review and meta-analysis were to determine the effectiveness and characteristics of severely energy-restricted diets in people with class III obesity. As there was a lack of publications reporting long-term dietary interventions and randomised controlled trial designs, our original publication inclusion criteria were broadened to include uncontrolled study designs and a higher upper limit of energy intake. Eligible publications reported studies including adults with class III obesity and that assessed a diet with daily energy intake ≤5000 kJ for ≥4 weeks. Among 572 unique publications from 4 databases, 11 were eligible and 10 were suitable for meta-analysis. Our original intention was to classify comparison arms into short-term (<6 months) and long-term (>1 year) interventions. Due to the lack of long-term data found, comparison arms were classified according to the commonalities in dietary intervention length among the included publications, namely dietary interventions of 4 weeks' duration and those of ≥6 weeks' duration. After a 4-week severely energy-restricted diet intervention, the pooled average weight loss was 9.81 (95% confidence interval 10.80, 8.83) kg, with a 95% prediction interval of 6.38 to 13.25 kg, representing a loss of approximately 4.1 to 8.6% of initial body weight. Diets ≥6 weeks' duration produced 25.78 (29.42, 22.15) kg pooled average weight loss, with a 95% prediction interval of 13.77 to 37.80 kg, representing approximately 10.2 to 28.0% weight loss. Daily dietary prescriptions ranged from 330 to 5000 kJ (mean ± standard deviation 2260 ± 1400 kJ), and had wide variations in macronutrient composition. The diets were administered mostly via liquid meal replacement products. While the included publications had a moderate risk of bias score, which may inflate reported weight loss outcomes, the published data to date suggest that severely energy-restricted diets, delivered via diets of varying composition, effectively produce clinically relevant weight loss (≥10% of initial body weight) when used for 6 weeks or more in people with class III obesity.

Effects of Two Preoperatory Weight Loss Diets on Hepatic Volume, Metabolic Parameters, and Surgical Complications in Morbid Obese Bariatric Surgery Candidates: a Randomized Clinical Trial

OBJECTIVE

To assess which type of preoperative dietary strategy is most effective in reducing liver volume and assessing its influence on different biochemical parameters and on surgical complications in individuals undergoing bariatric surgery.

METHODS

Parallel randomized trial comparing the effect of a very low calorie diet (VLCD) and a low calorie diet (LCD) for a period of 21 days before surgery on hepatic volume, anthropometric and biochemical parameters. Compliance and tolerance to the diets, surgical complications, and hospital stay were also determined.

RESULTS

Eighty-six morbid obese participants undergoing bariatric surgery were randomized. The hepatic volume was significantly reduced in both intervention groups, but no differences in changes between groups were detected. The reduction in the hepatic volume was higher in those patients with a baseline hepatic volume > 3 L compared to those with < 3 L (adjusted P value < 0.001). The percentages of total weight lost were 5.8 and 4.2% (adjusted P value = 0.004) for participants on the VLCD and LCD, respectively. There were no differences between groups for any of the biochemical parameters analyzed, nor in the number of surgical complications nor the length of hospital stay. Adherence to the diet was good; nevertheless, participants in the VLCD intervention showed worse tolerance.

CONCLUSIONS

In subjects with morbid obesity undergoing bariatric surgery, compared to a LCD, a preoperative 21-day intervention with VLCD is more effective in terms of reducing total body weight but not in terms of reducing the liver volume. Both types of preoperative diets have similar effects on clinical biochemical parameters, rate of surgical complications, and hospital length stay.