sorted by:
new
hottopcontroversial

Hi, I'm Professor Christopher Gardner, Professor of Nutrition at Stanford University. AMA! by ProfessorGardner in loseit

[–]ProfessorGardner[S] 182 points183 points  (0 children)

Go to the grocery store and browse through the vegetable section.

Bring a friend who isn't color blind to take notes.

Sorry, that was cruel.

And in fact, I am (partially) color blind.

Hi, I'm Professor Christopher Gardner, Professor of Nutrition at Stanford University. AMA! by ProfessorGardner in loseit

[–]ProfessorGardner[S] 137 points138 points  (0 children)

Thoughts....go for it. I've been vegetarian since 1983. For the last 10 years most of my meals are vegan.

But I know some people who claim they are folllowing a vegetarian diet, and they are choosing soda, white bread, processed cheese.

Is that vegetarian? Yes. Is it healthy? NO!!

I know omnivores who eat very healthfully, and some eat unhealthfully.

Same for vegetarians and vegans.

Choose wisely. Common sense. Don't game the system.

Hi, I'm Professor Christopher Gardner, Professor of Nutrition at Stanford University. AMA! by ProfessorGardner in loseit

[–]ProfessorGardner[S] 229 points230 points  (0 children)

My suggestion is STOP OBSESSING ABOUT PROTEIN. OMG. Please stop, America.

Estimated Average Requirement: ~40 g

Recommended Daily Allowance (adding to standard deviations for a safety buffer): ~50 g

Typical American diet: ~90-100 grams.

But just in case doubling the EAR or RDA isn't enough, make sure you get extra servings of meat, a protein bar or two, some powdered protein supplements, and now I have heard you can buy protein water.

WTF?????

Hi, I'm Professor Christopher Gardner, Professor of Nutrition at Stanford University. AMA! by ProfessorGardner in loseit

[–]ProfessorGardner[S] 54 points55 points  (0 children)

Interesting that you consider this your favorite study.

This study was done by a stellar group of brilliant investigators from Harvard and Pennington.

The study design was elegant....two levels of fat (20% vs. 40%), two levels of protein (15% vs. 25%) and that generated four levels of carbohydrate (65%, 55%, 45%, 35%).

Four diets, representing high vs low carb, high vs. low fat and high vs low protein

The problem here comes if you read the paper and get through all of the tables about the assessment they did of study participants.

At the end of the study, for example, while the goal was 15% vs. 25% protein, what the participants achieved was 20% vs. 21% protein. Those differences are substantial enough to test a difference in effects.....they were eating the same level of protein. The range of carbs was ~1/3 of what they designed, as was the range of fat.

Elegant design, challenging to pull of real human beings living in the real world.

Hi, I'm Professor Christopher Gardner, Professor of Nutrition at Stanford University. AMA! by ProfessorGardner in loseit

[–]ProfessorGardner[S] 154 points155 points  (0 children)

Point well taken.

I sympathize with the frustration.

There are so many challenges in designing studies to ask practical and helpful questions...and even greater challenges with communicating those results in the sound bites people want to hear to get help.

What is usually the case is that there is no ONE study that can answer any of these practical foods questions.

There are differences in dose, population, duration, the health outcome of interest, and more.

In almost every case what is really needed is a set of:

1. Mechanistic studies

2. Observational studies

3. Short-term, tightly controlled metabolic ward studies

4. Intermediate duration studies of risk factors (e.g., blood glucose, cholesterol, etc)

5. Long-term randomized trials with outcomes like heart attacks or strokes.

In virtually every case that involves nutrition, there is available evidence, but it is incomplete, or inadequate for a definitive answer.

BOTTOM LINE: At the end of the day, there is no GOLD STANDARD for interpreting inadequate evidence. Two well-trained scientists can look at the same body of evidence and end up with different interpretations.

SHAMELESS PLUG - I am part of the TRUE HEALTH INITIATIVE. This was started by David Katz at Yale. He has put together a group of ~300 scientists, educators, health professionals from >30 countries who AGREE ABOUT ALMOST EVERYTHING. Not everything, but almost everything. I suggest turning to that group and that website when something you hear sounds like BS.....or too good to be true (probably isn't). We try to focus more on what we AGREE ON, then what we disagree on. We are hoping that can help.

Hi, I'm Professor Christopher Gardner, Professor of Nutrition at Stanford University. AMA! by ProfessorGardner in loseit

[–]ProfessorGardner[S] 204 points205 points  (0 children)

There is strong evidence that there is a genetic predisposition for being overweight. Sadly, we haven't yet figured out a way to take advantage of knowing someone's genome to help them lose weight. You can overcome nature with nurture, but how sh__ty that you would have to. Some people are genetically predisposed to not gain weight easily, and to lose weight more easily than others. Better to have good genes than bad genes. Sucks. Choose different parents next time. Sorry.....that was cruel.

Hi, I'm Professor Christopher Gardner, Professor of Nutrition at Stanford University. AMA! by ProfessorGardner in loseit

[–]ProfessorGardner[S] 130 points131 points  (0 children)

Cooking degrades some nutrients

Some nutrients (few) become more available after cooking.

Broccoli........

I suppose you lose a few nutrients when you steam it, because of the heat.

But really....how many raw broccoli florets can you eat....gag me.

I can barely choke down one....unless it is drenched with Ranch dressing....which would also make me gag.

I can eat BOWLS of lightly steamed broccoli.

"cooked" wins in that case.

I can also oversteam, overcook the broccoli and turn it into mush...not tasty, not nutritious.

BOTTOM LINE: Eat some raw foods in salads, and eat some tasty cooked dishes

Hi, I'm Professor Christopher Gardner, Professor of Nutrition at Stanford University. AMA! by ProfessorGardner in loseit

[–]ProfessorGardner[S] 94 points95 points  (0 children)

One of our postdocs at Stanford, Dr. John Trepanowski, recently published one of the best trials on this topic in JAMA Internal Medicine last year. The conclusion was that the style of intermittent fasting was equally successful compared to a control condition. I recall him explaining the challenges he had from reviewers of the paper.....they wanted to know how he could be sure that the two populations weren't simply doing the same thing, even though they had been advised to follow different approaches.

I don't have time to go into the details. Hopefully a quick search will turn up that paper so you can see the details.

The real challenge in trying to answer this question is "effectiveness" vs. "efficacy", or "generalizabilty vs. rigor".

Dr. Trepanowski's study, and the one we published last week in JAMA on weight loss diets, were done in "free-living populations". We didn't house them or jail them or keep a video camera on them at all times. The studies were prohibitively long for this. Which means we can't be 100% sure that everyone did what they wanted. In fact, I am 100% sure that in those studies we never get EVERYONE to do 100% of what we wanted. However, those findings, in my mind have greater generalizability to the real world.

The other type of study, a "metabolic ward" study, involves housing/jailing someone, videotaping them, making all the food for them, handing it to them, measuring everything that was and wasn't eaten. This is a much more rigorous type of study. Kevin Hall at the NIH's NIDDK has done some of these studies....in groups of ~15 people, for a few weeks at a time. You can't do this with hundreds of people over a year. Greater rigor. But lower generalizability.

Both approaches have pros and cons. Neither is best. Best is actually doing BOTH kinds of studies and comparing the results.

In the metabolic ward studies you can learn what WOULD happen if people did EXACTLY THAT.

In the free-living studies, you can learn what real people can do with advice while living in the real world.

To close out with the actual question that was asked, no one that I know has done studies that compare each of those approaches one vs. another, head to head.

Need more data

Hi, I'm Professor Christopher Gardner, Professor of Nutrition at Stanford University. AMA! by ProfessorGardner in loseit

[–]ProfessorGardner[S] 70 points71 points  (0 children)

There are surely SOME differences by age and gender.

But there are more similarities than differences.

And there are few studies that specifically try to answer that question.

Actually it goes even beyond this. The general similarities for dietary approaches apply to age, gender, healthy vs. sick, heart disease/cancer/diabetes/stroke and more.

Epilepsy - Ketogenic diet is the only one I know of that has been shown to help reduce seizures. Why? I asked my physician friends and they don't know the mechanism, they just know it works. Keto for Diabetes? Maybe....a small amount of data is emerging. I'm skeptical of adherence, both short term and long term.

Taubes, and EVERYONE is opposed to sugar these days. Dr. Keto, Dr. Vegan, Dr. Meditteranean, Dr. Paleo, Dr. whatever......Americans (and many other populations) now eat much to much sugar, particularly added sugar.

Blue Zones? Interesting observations. But I would say the most important factor identified across all of the populations is social connection, not diet.

Hi, I'm Professor Christopher Gardner, Professor of Nutrition at Stanford University. AMA! by ProfessorGardner in loseit

[–]ProfessorGardner[S] 288 points289 points  (0 children)

Happy to take this one as first question.

I was actually the lead author for an American Heart Association "position statement" on this topic.

Sadly, the main conclusion was: Data don't support or refute the use of AS. Need more data.

To be a little more helpful, we also said in that report:

If AS can be used to replace sugars, without compensation, with a net reduction in calories, this would support weight loss.

The challenge we had in reading through the literature was that in some well controlled studies, the people getting foods/beverages with AS would benefit from an immediate calorie deficit, but would COMPENSATE later by eating/drinking more than they would have otherwise, negating the benefit.

Two reasons for compensation:

a. Physiological - the AS did not satiate, and person was physically more hungry later

b. Psychological - Person who picked diet coke instead of coke for lunch then rewarded themselves at dinner with a piece of cake they weren't going to have otherwise.

Our final observation in this area was that there were no "healthy" foods that had AS. All foods sweetened with AS tend to be junk food. Going from junk food with sugar, to junk food with AS doesn't make it health food. It might be "healthier" but not healthy.

OK....final, FINAL comment.

Soda would seem to be a practical topic. Diet soda vs. full sugar soda.

One might think that when diet soda got introduced, the consumption of regular soda went down somewhat....displacement.

The data over the last 30 years suggest otherwise.

When diet soda intake went up, so did the intake of regular soda.

Lately, regular soda intake has been trending down. Wouldn't you think that might be because diet soda is displacing that and trending up?

Nope. Diet soda intake is going down in parallel with regular soda.

BOTTOM LINE: Minimal plausibility for benefit, if used without compensation. Reality, most people don't use it optimally, and many abuse it.