Monday, November 10, 2014

Vegan diet best for weight loss even with carbohydrate consumption, study finds -- ScienceDaily

Vegan diet best for weight loss even with carbohydrate consumption, study finds -- ScienceDaily

"Even with carbohydrate consumption..."  LOL!  It amazes me that the idea that eating carbohydrates impedes fat loss has such a grip not only on laypeople, but also on scientists who I would expect to be better informed.

From Science Daily:

"Weight loss was not the only positive outcome for participants in the
strictly vegan group. They also showed the greatest amount of decrease
in their fat and saturated fat levels at the two and six month checks,
had lower BMIs, and improved macro nutrients more than other diets.
Eschewing all animal products appears to be key for these positive
results. 'I personally was surprised that the pesco-vegetarian group
didn't fare better with weight loss. In the end, their loss was no
different than the semi-vegetarian or omnivorous groups,' McGrievy said."
It really isn't a surprise to me.  In Powered By Plants I already discussed the significant body of research that indicates that eating animal products promotes wait gain, overweight, and obesity.   The probable mechanisms include:

  • Animal products tend to have a higher caloric density (kcal/g) and are less bulky than most plant products, so that when the diet consists of whole plant foods it is physically more difficult to over-consume calories.
  • Animal products contain no dietary fiber and are consequently more digestible than most plant products, so when the diet is rich in whole plant foods with no animal products there is greater fiber-related satiety and a lower net caloric absorption [1].
  • Animal products tend to have more total fat than most plant products, and dietary fat is less satiating per kcalorie consumed and becomes body fat much more easily than either carbohydrate or protein from plants.  Fish oil supplementation has even been found to increase appetite [2], which may help explain why the pesco-vegetarian group in the above study achieved no better weight loss results than consumers of land animal products.
  • Animal products tend to contain more saturated fat than plant products, and saturated fats tend to reduce insulin sensitivity [3], reducing glucose delivery to cells which may stimulate appetite, particularly for high energy density sweets and desserts or liquid sugar solutions.
  • Animal products contain less glucose than plant products, and glucose is the preferred food of the central nervous system.  When animal products displace plant products, the reduced total intake of and gut exposure to glucose and fructose may result in less satiation [4] than when consuming a plant based diet.  This may also be a cause for sweets cravings, resulting in over-consumption of desserts which typically have a high energy density due to their contents of fat and refined sugars.
  • Due to its higher content of essential amino acids, animal protein stimulates more fat-storing insulin release and less fat-mobilizing glucagon release than plant protein.  This is especially true when animal protein is combined with carbohydrates.  Animal protein may also decrease insulin sensitivity.  Therefore, replacing animal protein with plant protein favors fat oxidation over fat storage. [5, 6, 7
  • The more complex the food, the more energy expended to digest and assimilate its contents.[8]  Whole plant foods have very complex compositions.  A diet of whole plant foods involves a significantly greater post-meal diet-induced thermogenesis (expenditure of energy as heat) due to the presence of fiber and phytochemicals.[8]   


Sunny Sattva said...

Hi Don
Thanks for sharing and highlighting the salient points. I include small amounts of wild fish in my diet (5-7% calorifically) and weight loss is definitely slower than when 100% PB. However on balance I prefer to retain the fish and continue to lose slowly. For me the trick is to continue to include natural complex carbohydrates sources ie starch at every meal and not be tempted to exclude/reduce to compensate for the inclusion of the denser food. As you correctly surmise, when I have taken starch out of a meal, this mostly does lead to a craving for denser, sweeter foods, usually dried fruit, which I feel should be an occasional food. So the fish becomes more of a condiment, the starchy carbohydrate remains the centre of the meal, by volume. I hope it is OK to comment on fish as I know that you do not advocate consumption. Appreciate your work and your generosity in sharing this information.

Pablo Heitmeyer said...

What isn't provided is whether the weight loss was due to reduced muscle mass, which could be attributed to eating less protein. Simply losing weight due to eating less calorie rich protein isn't a desirable result for most people. Reducing your fat % of body weight is. Otherwise you'll just be thinner and squishy with no muscle tone.

In addition, the stated ability to 'eat carbs' while losing weight is misleading, even within the authors statement below, because pasta, rice, and breads are not the low-glycemic carbs that the study participants indulged in.

"The lead author on this study, Gabrielle Turner-McGrievy notes that the diet consumed by vegan participants was high in carbohydrates that rate low on the glycemic index. "We've gotten somewhat carb-phobic here in the U.S. when it comes to weight loss. This study might help alleviate the fears of people who enjoy pasta, rice, and other grains but want to lose weight," she said."

Don Matesz said...


This report states clearly that the vegan participants were only limited to eating plants, and rice, pasta, and other whole grains are both plants and also have a low glycemic load. Besides that, the glycemic load or index of a diet is a result of total diet composition, not individual foods.

Protein and carbohydrate have the same caloric content (~4 calories per gram) so I don't understand your comment "calorie-rich protein." Fat has the highest calorie density (9 kcal/g) but it does not support lean mass.

Furthermore, plants including whole grains all contain protein, and this study found that the vegans had the most desirable macronutrient balance.

I often consume more than 100 g protein daily from plants. There is no shortage of protein in a whole foods plant based diet. That's just a myth. I've posted on this blog many videos of my high protein plant-based diet.

Besides, muscle mass is primarily determined by type of physical exertion (i.e. resistance training), not by diet. Studies have shown that Americans eat about double the RDA for protein, yet they lose about 1/2 pound of muscle per year throughout their adult lives. Muscle is a "use it or lose it" tissue, not produced by eating protein, unless the individual goes from protein deficiency to protein sufficiency.

There are plenty of well-muscled people eating plant-based diets.

Eli Joseph said...

Really a great thanks for sharing such important points on losing weight. I also think that we should not do dieting. Our body needs vitamins and minerals too, so we can take Green supplements as a precautionary measure and these supplements helps in reducing weight quickly.