The Lowdown on Low Fat vs Low Carb

Researchers at Stanford University School of Medicine just published results from a 12-month study which aimed to identify which diet was the best – Low-carb or Low-fat. And the winner is…

Well, first, let’s see what were the basic questions (hypotheses) that the leader researcher, Professor Christopher Gardner  and his team were aiming to answer whether either of the following factors would dictate your success at losing weight:
  1. Genotype (that which predicts other factors such as your eye colour), or
  2. Baseline insulin secretion level (how much insulin your body produces to process glucose).

And the winner was?

Neither.

No evidence was found for the existence of a genotype or a baseline insulin level that would clearly favour your chances of losing weight.

Both diets resulted in an overall weight loss:

  • An average 13 pounds / 5.8 kg weight loss within the 609 study subjects
  • Wide variability – some gained as much as 20 pounds/9 kg while others lost as much as 60 pounds / 27 kg.

More detail about the methodology used can be found here.

Conclusions from the Research

Professor Gardner says “We have all heard stories of a friend who went on one diet – it worked great – and then another friend tried the same diet, and it didn’t work at all. It is because we are all very different, and we are just starting to understand the reasons for this diversity. Maybe we should not be asking what is the best diet, but what is the best diet for whom?”
His takeaway lesson from this study was that we should eat:
  • less sugar,
  • less refined flour,
  • more wholefoods (e.g. “wheatberry salad or grass-fed beef “), and
  • as many vegetables as possible.
Future projects are likely to focus on questions related to:
  • the microbiome (the billions of bacteria in our guts),
  • epigenetics (looking at gene expression rather than potential changes to the genetic code itself)

He goes on to say “I’m hoping that we can come up with signatures of sorts…I feel like we owe it to Americans to be smarter than to just say ‘eat less.’ I still think there is an opportunity to discover some personalisation to it.”

In his own words:

What Others Say

In the Telegraph article that discussed this research, they drew the conclusion that “the research showed the key to losing weight was simply eating less.”

Tam Fry, from the National Obesity Forum, a UK campaign group, said: “The best diet in town is not a fad but much less of what you actually fancy – and stick to it.”

Some Thoughts

The findings of the research do not surprise me at all. And I applaud some of the conclusions that Professor Gardner draws – cutting down on (refined) sugars/flours, eating more (plant) wholefoods and vegetables – but there are some issues that require clarification.

  1. When weight loss is the only factor considered, other issues related to the overall health-promoting aspects of nutrition are marginalised. There appears to be no stated justification for Professor Gardner’s jump from talking about the results of the research (genotype and insulin secretion levels) to then recommending specific nutritional elements (less sugar, more wholefoods etc). If he is going to make these statements (especially if he includes “grass-fed beef” in the list of healthy wholefoods), then it would be useful to see some justification for such statements – and, as we would suspect, any justification would not come from a study that simply focuses on weight-loss without also measuring other health factors (cholesterol, triglycerides, mineral/vitamin balance, etc).
  2. Professor Gardner’s statement “It is because we are all very different, and we are just starting to understand the reasons for this diversity. Maybe we should not be asking what is the best diet, but what is the best diet for whom?” is somewhat misleading. It suggests that there is no evidence from large population studies (such as the largest of them all, The China Study) that optimal health appears to depend on diet, to a large extent, irrespective of the individual genetic variations within the members of that population. Indeed, the Stanford University research itself dismisses the primacy of genetics or “insulin secretion levels” as markers for future weight gain, let alone the uncharted, and more vital area, of overall health gain.
  3. There appears to be a misunderstanding in the media about what conclusions can be drawn from the study. Professor Gardner says “I feel like we owe it to Americans to be smarter than to just say ‘eat less.’ The Telegraph, on the other hand, states that “the research showed the key to losing weight was simply eating less.” No wonder the public get confused. And to add more confusion, Tam Fry (National Obesity Forum) states “The best diet in town is not a fad but much less of what you actually fancy – and stick to it.” Again, the implicit assumption here is that all foods are equal, all diets that do not include “moderation in all things” are fad diets, and, again, the mistaken implication that the research is suggesting we should simply eat less calories.
  4. Professor Gardner’s comment “Maybe we should not be asking what is the best diet, but what is the best diet for whom?” is, for me, a frankly shocking indication that he may not have looked at the wealth of research demonstrating that there is one diet that has been proven to be optimal for human health – a whole food plant-based diet, with minimal or no animal protein. I suspect that if his research subjects had been rural Chinese, Papua Highlanders, Central Africans or Tarahumara Indians from northern Mexico, then he would not have even bothered to do this research study since more or less everyone within those communities would already have been at their optimal body weight, largely regardless of genome or insulin secretion level.
  5. When such research projects are taken up by the media and then the public, they are thrown back, once again, on the mistaken belief that nutrition is simply a matter of the quantity and not quality of the calories being “eaten”. People do not eat calories. They eat food. And our bodies are made out of the food we eat.
  6. Yet again, this research focuses in a reductionist manner on genetic and individual biochemical responses in order to establish something so vitally important to our populations’ health and well-being. It still makes me recall Nero fiddling while Rome burned…

In my experience and that of my clients, even increasing the amount of calories consumed after making the transition to a WFPBD (whole food plant-based diet) from a standard diet (whether it be a meat-based, vegetarian or vegan diet), can cause excess fat to drop off the body. Just as a vitamin C supplement does not cause the same bodily responses as compared to the vitamin C derived from eating an apple, the calories “consumed” from eating animal foods (whether processed or unprocessed) have a very different effect on the body than those derived from eating plant foods (whether organic whole plants or even less-healthy processed plant-foods). And the added bonus from eating a wide variety of organic whole plants represents yet another step in the direction of optimal health from eating those less-healthy processed plant foods.

There is yet to be mainstream coverage and acceptance of the only diet proven to reverse heart disease and other chronic diseases. In the meantime, looking after your own diet can have a greater effect on your health, encourage other people’s appetite for dietary change, avoid further damage to other species, and help protect the environmental welfare of our land, sea and air.

 

Quick Quiz - Lowdown on Low Fat vs Low Carb

(All answers are contained in the article.)

1. True or False: Reductionist research looks at the small details rather than taking a wider perspective?
2. Which particular diet is recommended by the researchers as being best for losing weight?
3. Which of the following are recommended by the researchers?


References

Gardner CD, Trepanowski JF, Del Gobbo LC, Hauser ME, Rigdon J, Ioannidis JPA, Desai M, King AC. AMA. 2018 Feb 20;319(7):667-679. doi: 10.1001/jama.2018.0245. Effect of Low-Fat vs Low-Carbohydrate Diet on 12-Month Weight Loss in Overweight Adults and the Association With Genotype Pattern or Insulin Secretion: The DIETFITS Randomized Clinical Trial.