A New Zealand study put the popular Intermittent Fasting, Mediterranean and Paleo diets to a comparative test over a year in a "real world" setting, writes MedicalBrief.
Intermittent fasting – whereby participants limit their energy intake to about 25% of their usual diet (500kcal for women and 600kcal for men) on two self-selected days per week, led to slightly more weight loss than the other diets. Bothe the fasting and Mediterranean diets improved blood sugar levels.
Co-lead author Dr Melyssa Roy, a research fellow in the department of medicine, at the University of Otago, New Zealand, says the amount of weight loss was modest – on average two to four kilograms for the 250 participants, but for those choosing the fasting or Mediterranean diets, clinically significant improvements in blood pressure were also seen.
The aim of the research was to examine how effective all three diets were in a "real world" setting, where participants self-selected which diet they wished to follow, without any ongoing support from a dietitian. Roy says the evidence shows that the Mediterranean, fasting or Paleo (Paleolithic) diets can all be "healthful, beneficial ways to eat", depending on the individual.
"This work supports the idea that there isn't a single 'right' diet – there are a range of options that may suit different people and be effective. In this study, people were given dietary guidelines at the start and then continued with their diets in the real world while living normally. About half of the participants were still following their diets after a year and had experienced improvements in markers of health.
"Like the Mediterranean diet, intermittent fasting and Paleo diets can also be valid healthy eating approaches – the best diet is the one that includes healthy foods and suits the individual."
The Mediterranean diet encouraged consumption of fruit, vegetables, whole-grain breads and cereals, legumes, nuts, seeds and olive oil with moderate amounts of fish, chicken, eggs and diary and red meat once a week or less.
The Paleo diet consists of mostly less-processed foods with an emphasis on eating fruit and vegetables, animal proteins, nuts, coconut products and extra-virgin olive oil. While "original" Paleo diets strictly exclude all legumes, dairy and grains, this study used a modified version including some dairy as well as up to one serving daily of legumes and grain-based food.
Co-lead author Dr Michelle Jospe, a post-doctoral fellow in the department of medicine, says the results showed people found the Mediterranean diet to be the easiest to adhere to. "Our participants could follow the diet's guidelines more closely than the fasting and Paleo diets and were more likely to stay with it after the year, as our retention rates showed."
Most of the 250 participants (54%) chose the fasting diet, while 27% chose the Mediterranean and 18% the Paleo. After 12 months, the Mediterranean diet had the best retention rate with 57% of participants continuing, with 54% still fasting and 35% still on the Paleo diet.
After 12 months, the average weight loss was 4.0kg for those choosing the fasting diet, 2.8kg on the Mediterranean diet and 1.8kg on the Paleo diet.
Reduced systolic blood pressure was observed among those participating in the fasting and Mediterranean diets, together with reduced blood sugar levels in the Mediterranean diet.
Jospe explains participants who said they were still following their diet at 12 months lost even more weight, showing the importance of choosing a diet that is sustainable. She believes the results of this study are relevant to the thousands of people following self-chosen diets with little supervision and indicates more realistic outcomes.
Researchers said the findings showed there was no “right” approach to diet, reports The Daily Telegraph.
Roy said: "In the real world, the one right way to lose weight and eat right is that you can find what suits you the best, and whatever diet is the best is the one you stick to.
"If you choose something that suits you, and is basically a selection of healthy foods, and perhaps eating a bit less often, you can actually get real-world benefits and just live a normal life, and lose weight and see improvements in your health."
Abstract
Background: Intermittent fasting (IF) and Paleolithic (Paleo) diets produce weight loss in controlled trials, but minimal evidence exists regarding long-term efficacy under free-living conditions without intense dietetic support.
Objectives: This exploratory, observational analysis examined adherence, dietary intake, weight loss, and metabolic outcomes in overweight adults who could choose to follow Mediterranean, IF, or Paleo diets, and standard exercise or high-intensity interval training (HIIT) programs, as part of a 12-mo randomized controlled trial investigating how different monitoring strategies influenced weight loss (control, daily self-weighing, hunger training, diet/exercise app, brief support).
Methods: A total of 250 overweight [BMI (in kg/m2) ≥27] healthy adults attended an individualized dietary education session (30 min) relevant to their self-selected diet. Dietary intake (3-d weighed diet records), weight, body composition, blood pressure, physical activity (0, 6, and 12 mo), and blood indexes (0 and 12 mo) were assessed. Mean (95% CI) changes from baseline were estimated using regression models. No correction was made for multiple tests.
Results: Although 54.4% chose IF, 27.2% Mediterranean, and 18.4% Paleo diets originally, only 54% (IF), 57% (Mediterranean), and 35% (Paleo) participants were still following their chosen diet at 12 mo (self-reported). At 12 mo, weight loss was −4.0 kg (95% CI: −5.1, −2.8 kg) in IF, −2.8 kg (−4.4, −1.2 kg) in Mediterranean, and −1.8 kg (−4.0, 0.5 kg) in Paleo participants. Sensitivity analyses showed that, due to substantial dropout, these may be overestimated by ≤1.2 kg, whereas diet adherence increased mean weight loss by 1.1, 1.8, and 0.3 kg, respectively. Reduced systolic blood pressure was observed with IF (−4.9 mm Hg; −7.2, −2.6 mm Hg) and Mediterranean (−5.9 mm Hg; −9.0, −2.7 mm Hg) diets, and reduced glycated hemoglobin with the Mediterranean diet (−0.8 mmol/mol; −1.2, −0.4 mmol/mol). However, the between-group differences in most outcomes were not significant and these comparisons may be confounded due to the nonrandomized design.
Conclusions: Small differences in metabolic outcomes were apparent in participants following self-selected diets without intensive ongoing dietary support, even though dietary adherence declined rapidly. However, results should be interpreted with caution given the exploratory nature of analyses.
Authors
Michelle R Jospe, Melyssa Roy, Rachel C Brown, Jillian J Haszard, Kim Meredith-Jones, Louise J Fangupo, Hamish Osborne, Elizabeth A Fleming, Rachael W Taylor
[link url="https://www.otago.ac.nz/news/news/otago731558.html"]University of Ortago material[/link]
[link url="https://academic.oup.com/ajcn/advance-article-abstract/doi/10.1093/ajcn/nqz330/5687899?redirectedFrom=fulltext"]American Journal of Clinical Nutrition abstract[/link]
[link url="https://www.telegraph.co.uk/news/2020/01/24/slimmers-52-diet-lose-twice-much-weight-trying-paleo/"]Full report in The Daily Telegraph[/link]