Science Catch-up. Low-Carb Mediterranean Diet For Fat Loss?


by Alejandra "Alex" Ruani — Get free science updates here.

Welcome to our Thursday Science Catch-up: curated links by The Health Sciences Academy. Get our email updates every other Thursday here (it’s free).

Let’s catch you up with studies and news that recently made the headlines!

Click on your favourite topics to read our summary:

1. Low-carb Mediterranean diet for fat loss?

2. High intensity exercise may give your memory a boost

3. Random eating times and triglycerides

4. Should we pick a diet based on our genes?

 

Low-carb Mediterranean diet for fat loss?

Study link

When we hear about the Mediterranean diet, we often associate it with bread and pasta…

But in this case scientists wondered: what if we make it low carb?

Could that help with fat loss?

A recently published trial investigated changes in the adipose tissue of 278 overweight adults who were randomised to either follow a low-carb Mediterranean diet, or a low-fat diet for 18 months.

In this study, the scientists used a technique known as Magnetic Resonance Imaging to detect body fat changes before and after the intervention.

The results were intriguing…

Those in the low-carb Mediterranean diet group experienced significantly greater reductions in visceral fat compared to the low-fat diet. This fat loss was seen even in individuals who didn’t lose any weight.

The Mediterranean/low-carb diet (right side) induced greater visceral fat (IHF) loss compared to the low-fat diet (left side) during 18 months (Gepner et al., 2017).

This outcome is ideal, because visceral fat is fat that builds around your organs, harming them over time.

So how much carbohydrate did this low-carb Mediterranean diet include?

The participants ate less than 40 grams of carbs a day in the first 2 months. But unlike other low-carb diets, this one was higher in fibre, with loads of vegetables and legumes, and white meat replacing red meat.

The scientists also flashed out that individuals who lost fat surrounding the liver showed marked improvements in insulin sensitivity, which is a desirable metabolic advantage.

This is a useful reminder that metabolic health isn’t improved by weight loss on its own, and that body composition (fat vs muscle mass) matters, too!

If you found this interesting, click here to learn how a low-carb diet can affect your appetite.

 

 

High intensity exercise may give your memory a boost

Study link

Do you consider yourself an athletic person? Or have you ever felt mentally refreshed after a good sports session, sensing that your concentration was maxed out?

A recent scientific study supports this notion…

Researchers wanted to see the effects of exercise on two types of short-term memory, known as high-interference and general recognition.

This study recruited 95 young healthy participants and split them into either one of 3 groups: exercise training, exercise + cognitive training or no training (control).

All the participants completed a memory function test before and after the 6 weeks of finalising the study.

This test examined the speed of the participants to discern between images they had previous been shown, and new but similar images. This kind of aptitude is known as high-interference memory.

Additionally, the general recognition memory task involved recognising and identifying previously viewed images that were identical.

And… what were the results?

Exercise, either alone or in combination with the cognitive training, showed significant improvements in high-interference memory.

Both the exercise training and combined training groups had better high-interference memory performance after 6-weeks compared to the control (no training) group (Heisz et al., 2017).

How exercise conferred these benefits on short-term memory is still unknown in humans, but similar experiments in animal models suggest that this is mediated by an increase in neurogenesis: extra generation of neurons!

Do you struggle to get on those trainers? Could your genes be determining how much you exercise? To learn more, check out our Science Report: How Genetic is your Level of Exercise – or Lack of?

 

 

Random eating times and triglycerides

Study link

A recent study used rats to investigate the influence that day-night eating had on fat clearance from the blood.

The researchers fed the rats with a fatty meal at either the beginning of their active period or rest period, to see if they responded differently to the food challenge.

Notice that unlike in humans who are diurnal, rats are active at night and they rest during the day.

Now, the results were remarkable…

The blood triglyceride levels remained higher for longer in rats fed during the day (ZT2), compared to the ones who received the meal at night (ZT14) (Moran-Ramos et al., 2017).

It was seen that the rats who were fed during the day struggled to clear the levels of triglycerides (a type of fat) from their bloodstream compared to the rats that had the meal at night.

This is important as triglycerides are a risk marker for cardiovascular disease.

While this study highlighted the negative impact that eating at the wrong time has in rats, the conditions of the experiment were very forceful and cannot be extrapolated to suggest that night-eating in humans causes heart disease, as some media outlets suggested when reporting this study.

Confused by conflicting news about night eating and weight gain? Get to the bottom of the debate by downloading our Science Report: Does Night Eating Make You Gain Weight?

 

 

Should we pick a diet based on our genes?

Study link

As we always say at The Health Sciences Academy: if it’s not personalised, it’s not effective.

And once again, another study reminds us of just that…

Here, scientists used four different groups of mice with distinct genetic profiles to assess the effectiveness of four popular diets (American-style, ketogenic, Japanese-style, and Mediterranean).

Effect of the 3 diets on several health markers in the four genetically distinct mice groups (A, B6, FVB, NOD) (Barrington et al., 2017).

The genetic differences between each group roughly reflected the differences you might find between unrelated individuals.

Interestingly, the study showed that differences in the genetic makeup had a huge impact on how well the mice responded to the diets.

For example, the ketogenic diet lead to improvements in glucose metabolism and body composition in two strains of mice… but another group of mice reacted adversely and developed insulin resistance!

These genetic differences also lead to strain-specific changes in metabolic profile in response to the other three tested diets.

Although this study was conducted in animals, it should act as a warning that what works for you may actually harm another individual!

Might your distant ancestral past hold the key to why some people thrive on diets with marked differences in macronutrient composition? Dive into evolutionary genetics to find the answers by downloading our Science Report: Nutrigenetics 101: Eating Right For Your Genes.

 

 

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The-Health-Sciences-Academy-Alejandra-Ruani-small1-right Alejandra "Alex" Ruani leads the research division at The Health Sciences Academy, where she and her team make sense of complex scientific literature and translate it into easy-to-understand practical concepts for their students. She is a Harvard-trained scientist and UCL doctoral researcher who specialises in cravings and appetite neurobiology, nutrition biochemistry, and nutrigenomics. Besides investigating and teaching the latest advances in health and nutrition science, Alex makes it easier to be smarter with her free Science Catch-ups.

Connect with Alex via email.


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3 Comments

  • michael Bryan burns

    Reply Reply January 25, 2018

    Thank you so much for bringing the” Improving metabolic health through precision dietetics in mice. “study to my attention. I did notice that the mice all benefited from the Japanese diet. That diet drew my attention a few years ago when I was first studying oncology. I wanted to know why a person who lived in a small rural Japanese town eating a traditional diet, and then moved to the city , started to develop diseases..including cancer. The environment played a part, the stress levels yes, but it was the diet changes that were my focus! Thats what I wanted to see, what they were eating in the mountain villages, and what they were eating when they moved to a big city. I have now spent years studying the molecular biology of the foods and spices…for instance the Lotus root, and its effect on cytokines that we now know effect an inflammatory response to antigens. This selective immunomodulation through diet choices such as isoflavones in soy, or glucans in mushrooms, is very promising.
    I feel very fortunate to be a part of your community, and encourage you to look for the answers that will save lives and improve the quality of life for all of those around us!
    Sincerely,
    Michael Burns

  • Dawn Hutchins

    Reply Reply January 25, 2018

    In the first study, it would be interesting to find out exactly what sort of diet the low fat group was eating. I assume the LC Mediterranean was vegetables, seafood, oils and walnuts. I read the conclusion. I find it so ridiculous/funny how they word some of these things.

    Here is my laywoman’s translation: Conclusions – Moderate weight loss alone doesn’t really reflect the significant lifestyle effects on fat deposits that both promote the formation of fatty plaques in the arteries and that produce heart disease and diabetes.

    The Mediterranean, low carb diet mobilizes fat deposits that are in an abnormal place or position, and exercise has its own contribution to visceral adipose tissue loss.

    Fat depots show different responses and are related to your risk of having diabetes, heart disease or stroke. Different lifestyles might begin to gather fat from different anatomical sites.

  • Ruti a chang

    Reply Reply January 29, 2018

    Hi Michael ,

    I am only a student on this course but if there is anything direct you feel would aid your reseaarch , please not e that I am more than happy to try and join with what you are studying.

    My interest is especially the temporary aspects of sudden conditions presenting for no apparent reason but taken severely and in many cases near fatal conditions which present after a move from the place a person has moved from to another more beneficial environment. Little to no dietary changes have caused a trigger, then a switch of diet and the person suffers – or is presented with- a huge amount of conditions which were never seen genetically or otherwise in any member of the family. The one off child of a mother who had changed her home or diet in such a small way causing a catalyst of effects and no other key factor to explain the conditions suffered by either mother or newly born infant.

    i too feel equally fortunate to be a part of thhis community and appreciate the opinions and criticism which may befall me . Renewing the knowledge one has or has lost can never be underestimated . When it is keeping us alive- shout from the rooftops.

    Ruti A Chang

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