This is what the keto diet does to your body | Professor Christopher Gardner

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Published 2022-07-11
Keto has been promoted as a magic bullet for weight loss by its supporters and slammed as dangerous by its opponents. It's no surprise - completely removing almost all carbohydrates is not what most people consider ‘a balanced diet’.

With carbs off the table, Keto diets involve a dramatically increased fat intake. At the same time, drastically reducing carbs means starving our gut microbes of the fiber that feeds them.

Nonetheless, doctors prescribe keto diets to treat people with severe diabetes and see dramatic improvements, and many healthy people swear by keto for weight loss. On top of this, removing carbohydrates prevents blood sugar spikes and crashes linked to inflammation and disease.

In today’s episode, Jonathan speaks to a leading nutritional researcher to understand whether or not keto diets are a crazy fad:

Christopher Gardner is a professor at Stanford University and a member of ZOE’s scientific advisory board who’s produced a clinical trial of keto diets, published in the American Journal of Clinical Nutrition.

If you want to uncover the right foods for your body, head to joinzoe.com/podcast and get 10% off your personalized nutrition program.

Timecodes:
00:00 - Intro
00:10 - Topic introduction
01:37 - Quick-fire questions
05:30 - What is a ketogenic diet? How does it work?
08:58 - Why have people become interested in keto?
10:51 - To promote ketosis, how low-carb should a diet be?
12:29 - Why are randomized trials so important?
15:30 - Christopher’s study
19:56 - What is a Mediterranean diet?
22:58 - Study results
27:14 - How sustainable is a keto diet?
33:20 - How strictly should you follow the keto diet?
34:52 - Diabetes and keto
38:03 - Keto’s impact on the microbiome
40:25 - Is there a long-term impact on the ability to process carbs?
42:25 - Summary
44:29 - Listener’s question
45:05 - Goodbyes
45:27 - Outro

Books:
- Every Body Should Know This by Dr Federica Amati: amzn.to/4blJsLg
- Food For Life by Prof. Tim Spector: amzn.to/4amZinu

Episode transcripts are available here: joinzoe.com/learn/category/nutrition/podcast

Read Christopher's Study here: academic.oup.com/ajcn/advance-article/doi/10.1093/…

Follow Christopher: twitter.com/GardnerPhD

Follow ZOE on Instagram: www.instagram.com/zoe/

All Comments (21)
  • @SusanBame
    Healthy keto saved my life. I've been pain-free and type-2-diabetes-free since 2017. Never going back to eating carbs, sugars and processed oils. Yes, it's a restrictive diet: it restricts the pain right out of my body and I am so grateful.
  • I have been following the keto lifestyle for 3 years and love it. I lost 120 pounds and my prediabetes is resolved. At 61, I am healthier than I have been for 30 years. i can even bend over and tie my shoes without blacking out. My blood work is excellent and my body weight is where it should be. One thought, all of the major food manufacturers and Pharma hope we do not take up this lifestyle, they will go broke.
  • @maraft
    I am 85nyears young and have been on a keto programs for the past 5 years. When I started the program I was aiming for no more than 20/30 gms a day, making up the balance with 70 % fat and 30% protein. I ate red meat once a week and the balance made up of 50% fish, 50% chicken/turkey (usually dark meat). I lost weight, I lowered my A1C from 9.0 to 5.5 and have not felt better in many years. I now eat only 2 meals a day, fasting for 16 to 18 hrs. each day. Occasionally when we go out for dinner, I will cheat a little and have some bread. One of the most important aspects of my way of eating is that I record all the food I eat and I'm honest. I try to follow the program that Dr. Eric Westman recommends. He is a professor at Duke University. I too am very happy doing Keto. Best wishes to all.
  • @Spomky_Original
    I've been keto/ketovore for 2-1/2 years and at 74 am healthier than I have been in decades. It has restored my health and my doctors just say, 'Keep doing what you're doing." I am not bored with my diet nor do I ever intend to go back to a high carb diet.
  • Sauerkraut, Kemchi, Natto, whole fat yogurt and Kefir are great for the gut microbiome!! You can also get fibre from cruciferous and leafy green veggies. Being on Keto and Intermittent fasting, for 5 years , I've eliminated beans and whole grains from my diet and my blood markers have been consistently great. I'm 64 and it's the best I've ever felt in my life. 👍🏽
  • I'm going to add my two cents. I spent all of my fifties and half of my sixties gaining, gaining, gaining. Extreme stresses in my life caused me to eat too much, too often and the WRONG foods. When I finally came to realize that all this eating was my way of dealing with emotional/psychological feelings from those stresses was wrecking my life. Ended up with high blood pressure and prediabetes. Overweight by more than a hundred pounds. When I finally decided my health was more important than anything I began with Keto eating, eventually including some intermittent fasting. I've now lost 90 lbs, can finally exercise again and feel so much better. My doctor agrees. Blood sugar/AC1 is great. Blood pressure down. I DO eat carbs. However, the carbs I eat are broccoli, zucchini, greens/spinach/romaine, turnips, bell peppers, radishes. . .and so on. We eat very healthy. As far as I'm concerned I would rather do without the pasta, bread and other starches and keep my health. As are as the food pyramid is concerned, it was developed to help farmers sell their wheat, barley, corn etc, not for the good of people in this country.
  • @octobermoon9
    I've been Keto/Carnivore for 13 months and have never felt better. No longer pre-diabetic, no aches or pains even after a good cardio workout, always have energy and sleep very well. Being healthy isn't profitable, will put a whole lot of people in mainstream medicine out of work and take a serious chunk out of the pharmaceutical industry.
  • I've been doing keto for the last few months and feel fine, weight loss is continuing steadily. What struck me was when I go shopping, probably in a supermarket, that there is aisle after aisle of carbohydrates - breads of all sorts, cakes, crisps, pasta, rice, sweets, sweetened drinks, etc, etc. Lots of processing, to make them seem different, tasty, but basically all carbs. It's no wonder there are so many people struggling with their weight in the UK!
  • @jo-lesley9590
    Whilst I was trying to eat well with carbs, my brain seemed to have a button with "eat" written on it that it would constantly push. Occasionally I felt I had no choice but to eat a massive meal, like being a junky on carbs, eat, eat, eat, jab, jab, jab. As soon as I switched to very low carb and full fat, that constant jabbing stopped. My body felt at rest for the first time in my life. I felt like I was giving my body what it needs. So adherence is absolutely no problem at ALL. I am reducing my carb intake more and more as I learn more, and I will never go back. Be careful of thinking that grains are such an important part of our evolution, the foundations of our body makeup happened long before they were used.
  • @annrhodes3544
    The fiber issue is easily solved. I add acacia fiber to every meal every day. I find no problem fasting 23 hours out of every 24 and eating one keto meal per day. I am in remission from chronic lymphocytic leukemia, I have lost 47 pounds, my A1c is 4.9, I am 79 years old and my health and my labs are excellent.
  • @sandykerr3872
    My husband is on the autism spectrum and the most amazing outcome of a clean ketogenic diet (3 years) is that all his sensory issues are so dialed down that he's like an entirely different person, so much so that he calls himself 2.0 (a genuine upgrade). At 57 he experienced the emotion of "happiness" for the first time ever in his life and now he is happy most of the time and both of us have eliminated all our health issues. Eating this way is for life and we don't miss any foods, so it's not sacrifice for a 100% improved life for us both. We also won't be holding our breath waiting for so-called "nutritional science" to disentangle from big business long enough to actually care about people's health. I was a health researcher, so my cynicism comes from being an insider and seeing what actually goes on.
  • @1welshdevil
    18 months on keto, 11 stone off and back to the gym, it's worked for me. I still cannot understand the misconceptions around it. Grains and alcohol, not sure I can see the health benefits from either. On keto, I do have vegetables and fruits, again, the misunderstandings are crazy. Keto helped me reverse pre diabetes, I no longer need to take anti inflammatory meds either.
  • @gwynhyfer
    I was bedbound at 50 with ME/CFS for nearly ten years after a severe throat virus. Limiting my carbohydrates means that at 60 I am able to lead a relatively normal life once more - DIY, gardening, riding, etc. Somtimes I drop off the wagon and have bread or cake and within days I begin to have severe joints pains and feel the fatigue coming back. I'm not a keto devotee but low carbs/high protein definitely helps me manage my symptoms.
  • I was on Keto for about 2 years prior to the pandemic, and lost 100 pounds. Once we had all the shortages at the grocery stores, it became difficult for me to stay on it. I went off Keto and gained all my weight back plus some. A couple months ago I went back on it and am down 30 pounds.
  • @tiggy181
    I started a low carb - not strict keto - when I was diagnosed with T2 diabetes over 5 years. I am not 'high fat', I did not drastically increase fats. I still eat foods with fibre. It does not get boring or unpalatable. I actually eat many vegetables I never tried before. And my diabetes has been in remission for 5 years.
  • I have been doing Keto and IF for months now and the outcome has been nothing but positive! I’m 54 years old and my CBC blood panel is outstanding! I have lost weight and don’t miss bread at all. I will continue this lifestyle due to the excellent results I have obtained.
  • @jmartin4886
    I have never eaten more leafy greens, broccoli, celery, asparagus, mushrooms and avocados than I do now on my healthy whole food keto diet. I also eat 3 tablespoons of chia seeds every day for even more fiber. I get way more fiber than I did before starting keto.
  • @vernaxxx8940
    After the festive season, I have to say that the major problem in staying on a restrictive diet such as keto is OTHER PEOPLE. No matter how clearly you inform people that you are staying with, or are staying with you, that you do not eat certain things, you find that they do not respect this. They even decide to pressure you to eat them, or sneak them into things that are served to you. I've even had a relative go shopping and place shop-bought cake in my fridge, as one example. She said "I thought you were losing too much weight"(my BMI is 26, she is obese). The last relly went home 4 days ago and it's going to take a while to clear my fridge of stuff he bought. Some can go in the freezer, some stay in the pantry til I have visitors again. I'm unclear whether this behaviour is a lack of understanding, or a desire to sabotage your diet, maybe because they feel you are pretending to be superior to them? Anyway, I recommend living on your own, as fortunately I do, if you want to stick to dietary restrictions.
  • @irwingarcia398
    HyperKeto isn't just about losing weight—it's about reclaiming your vitality and optimizing your health from the inside out. By adopting a ketogenic lifestyle with HyperKeto, you'll experience a myriad of benefits beyond the scale. From increased mental clarity and focus to stabilized energy levels throughout the day, the positive effects are truly profound. Plus, with the abundance of mouthwatering recipes and meal plans provided, sticking to the program becomes effortless. Don't just imagine a healthier, happier you—make it a reality with HyperKeto.
  • Reading the comments suggests a huge number of people have benefited from keto and are adhering to it in one form or another because they can really feel the health benefits. These comments are in stark contrast to the suggestion from the prof’s study of 40 people for a short period that Keto didn’t do much compared with a Med diet. I’ve just started Keto (2 weeks in) and am already feeling much better - esp reduced pain from inflammation. Not something I have experienced when eating my extremely “healthy” Med diet. The lack of craving is brilliant.