Tim Noakes’ revival of a 150-year-old high-fat, low-carbohydrate Harvey Banting diet has been roundly condemned by the medical establishment. Potassium-rich foods can lower the risk of high blood pressure, stroke, and heart disease. Here's how to get more potassium in your diet. High-protein, low-carbohydrate diets, like The Atkins Diet, have been widely promoted as effective weight loss plans. These programs generally recommend that dieters. On the second experiment, five men consumed a high fat diet (10% P, 73% F, 17% C) and five a high carbohydrate diet (10% P, 23% F, 67% C) for 56 days. Low Carb High Fat Diets and the Thyroid - Perfect Health Diet. Last year we ran a series on “Zero- Carb Dangers,” which are health problems that can appear if carb intake – or carb+protein intake, since protein can to some degree make up for a deficit of glucose – are too low. Anthony Colpo has recently argued that hypothyroidism should be added to the list of potential zero- carb dangers; and that low- carb high- fat diets in general might create a risk of hypothyroidism. Similar arguments have been made by Matt Stone and others. Our resident thyroid expert, Mario Renato Iwakura, decided to look more deeply into the matter. What does the literature say? There have been anedoctal reports on low carb forums about people becoming hypothyroid after following a low carb, high fat diet. Anthony Colpo recently wrote a blog post about carbohydrate, fat and protein intake and their effects on thyroid hormone levels, concluding that a high fat or high protein diet is detrimental and that a high carbohydrate diet is good for the thyroid . There is no evidence that a diet, such as the Perfect Health Diet, that is high in saturated and monounsaturated fat, low in PUFA, and provides sufficient, moderate levels of protein and carbohydrate, has any detrimental effect on the thyroid. On the contrary, I believe that such a diet is optimal for thyroid health. What Has Been Tested: High PUFA Diets. Colpo’s post is extensive and covered most, but not all, relevant studies published to date about the subject. Many of those studies have problems like short duration or calorie restriction. But in almost all, with the exception of one study by Jeff Volek and collaborators . An example is the Vermont long term study . The excess fat in these diets averaged 8. So, this diet’s fat was probably 1. Or in Ullrich et al 1. All diets were in liquid form, and fat was predominantly PUFA. The composition of the four diets was: 5. P/1. 0C5. 0P/7. 6C7. P/1. 0C7. 0P/8. 6CEnergy (kcal)5. Protein (% cal)3. Fat (% cal)5. 7. 8. Carb (% cal)6. 7. T3 Day 0. 2. 0. 2. How can you tell if your belly fat is putting your health at risk? No special blood tests or scans are required. All you need is a tape. The Perfect Health Diet. Here’s our Perfect Health Diet food plate: NOTE: This is our new food plate, updated 2015. Foreign translations of the original food plate. People who avoid carbohydrates and eat more fat, even saturated fat, lose more body fat and have fewer cardiovascular risks than people who. Home > Body Type Diet > Apple Shaped Body. Apple Shaped Body Diet & Workout Tips to Get the Pounds Off and Reduce the Health Risks of Your Female Body Shape. T3 Day 2. 81. 1. 1. Variation- 4. 5%- 2. T3 thyroid hormone levels decreased on all of these severely calorie restricted diets. However, when PUFA was high (5. P/1. 0C and 7. 0P/1. C) the decrease in T3 was much larger than when PUFA was low (5. P/7. 6C and 7. 0P/8. C). In a 1. 99. 2 paper, Vasquez et al compared two very low calorie diets (6. The fat sources were soybean oil and refined and stabilized vegetable oils. Ketogenic. Nonketogenic. Protein. 35%3. 4%Fat. Carbs. 9%5. 1%T3 Day 0. T3 Day 2. 80. 8. 1. Variation- 4. 3%- 1. The various studies cited by Colpo also show decreases in T3 levels in diets high in PUFA. In Ullrich et al 1. Thyroxine (T4) and reverse T3 (r. T3) did not change significantly. Having high cholesterol puts you at risk of developing heart disease, the leading cause of death in the United States. Learn about diet, causes, and more. Lower fat isn't necessarily better. Regularly consuming fewer than 20% of your daily calories from fat (see "Too Low" on the chart above) will put your health at risk. Thyroid- stimulating hormone (TSH) declined equally after both diets”In the Vermont study . When subjects on the low- carb diet began eating the higher- carb mixed weight gain diet, their T3 levels rose. T3 levels among those who went from the high- carb maintenance diet to the mixed diet remained unchanged. In contrast to T3, serum concentrations of T4 were unchanged by overeating or changes in dietary composition.” . Neither do we have studies showing what happen to T3 levels after a high saturated/monosaturated fat diet is eaten. We will have to rely on indirect evidence. Indirect Evidence: Calories Required to Maintain Weight. There is a connection between thyroid activity and obesity. Reduced thyroid activity reduces energy expenditure (“calories out”) and promotes weight gain; normal thyroid function tends to promote normal weight. So we can use the vast number of obesity studies as indirect evidence for the effects of different types of diet on the thyroid. Anthony emphasized this relationship in his post, noting findings of the Vermont study on overfeeding: “Again, that both groups gained weight should come as no surprise. However, the group overfed the mixed diet required more calories (2,6. Baseline differences in metabolism between the two groups were ruled out, as there was no difference in total calories required to maintain initial lean weights.”So the high- PUFA diet promoted weight gain: it caused excess weight to be retained at a lower calorie intake. This is consistent with reduced thyroid activity. Is this effect due to a high- fat diet generally, or to high- PUFA diets only? Some insight into this question may be found in a blog post by Stephan Guyenet . Rats fed isocaloric diets in which the fat source was varied among three groups – a beef tallow group (primarily saturated fat, 3% PUFA), an olive oil group (primarily unsaturated, 1. PUFA), and a safflower oil group (7. PUFA) – had highly variable weight gains. The olive oil group gained 7. Here is the data, expressed in terms of the percentage of baseline calorie intake that the men had to eat to maintain their weight: The high- fat diet consisted largely of butter and cream; the high- carbohydrate diet of extra sugar. When eating the butter and cream, subjects had to eat more calories to maintain weight than when eating the sugary diet – 2. Every subject had to increase calories when eating high- fat. This suggests higher thyroid hormone levels on the high- saturated fat diet than on a high- carb diet. The Volek Study. Anthony cited a study by Jeff Volek and others . There was a significant increase in total T4 (+1. T3 nor r. T3. They instead tested T3 uptake, an indirect measure of thyroxine binding globulin (TBG) in the blood, which tells us little of any real value about changes in actual thyroid hormone levels. The researchers also measured IGF- 1, glucagon, total and free testosterone, sex hormone- binding globulin (SHBG), insulin- like growth factor- I (IGF- I), and cortisol. The only significant change noted was a reduction in insulin following the low- carbohydrate diet. The Volek study is very interesting because it was not calorie restricted (only carbohydrate was restricted) and was done in normal- weight man. The amount of polyunsaturated fat increased a little (from 6 to 1. Although he did not directly measured T3 nor r. T3 we have indirect evidence that they were not impaired. One very well known fact is that hypothyroid patients, even when taking T4 hormones, usually struggle to lose fat. This occurs because, when thyroid hormones are low, especially when T3 (triidothyronine) is low . If the LCHF diet was impairing the thyroid these healthy normal weight men, who had been advised to eat enough calories to maintain their weight during the intervention, should have struggled to lose fat mass. In fact they lost 3. The control group did not lose any weight despite an 1. More, testosterone levels usually decrease when thyroid hormones are low . IGF- 1 levels are also decreased in hypothyroidism . Glucagon levels are higher in hypothyroid patients . Sex hormone- binding globulin (SHBG) is low in hypothyroidism . But none of these parameters changed during the LCHF diet. So this diet which was low in carb (8% of calories) and moderately high in protein (3. PUFA (1. 1%) does not seems to affect the thyroid if saturated and monosaturated fat (5. Let’s compare the fatty acid profile of the Volek diet with that of human milk: Saturated. Monounsaturated. Polyunsaturated. Volek diet. 41%4. Human milk. 47. 5%4. Not too much difference. Perhaps PUFA intake needs to be higher than 1. Effects of high fat and thyroid responses to cold. In 1. 94. 5, Mitchell et al published two articles comparing the effects of proteins versus carbohydrates and fat versus carbohydrate on man’s tolerance to cold exposure . Carbohydrate does better than protein, but worse than fat, at maintaining internal temperature as measured by rectal temperature. On the first experiment, five men consumed a high protein diet (4. P, 4. 0% F, 1. 9% C) and five a high carbohydrate diet (1. P, 4. 1% F, 4. 8% C) for 5. Food intake was adjusted to mantain a constant body weight. The effect of decrement in rectal and mean skin temperature during eight hour exposure to cold with light clothing: Rectal Temp. Skin Temp. High Protein. High Carb. 1. 0. 53. Significance. P=0. P=0. 0. 09. 6On the second experiment, five men consumed a high fat diet (1. P, 7. 3% F, 1. 7% C) and five a high carbohydrate diet (1. P, 2. 3% F, 6. 7% C) for 5. Food intake was adjusted to maintain a constant body weight. The excess fat of the high fat group was provided by butter and cream. Decrement in rectal temperature from the first two hour to the last two hours of 6 hours exposures to - 2. Eating a high carb meal between the intervention did not produced any alteration. But, eating a high fat meal cut the decrement in rectal temperature in half. Thyroid hormones are responsible for basal metabolic rate and heat production. So, if a high saturated fat diet maintains body temperature better than a high carbohydrate diet when the body is subjected to cold, it would seem fair to assume that the thyroid functions better on this high saturated fat diet. Conclusion. A diet with sufficient but not excess protein, moderate carbohydrate comprising a minority of calories, and high intake of saturated and monounsaturated fat but low intake of polyunsaturated fat would seem to be optimal for thyroid function. But this is the Perfect Health Diet! References. Is a Low Carb Diet Bad For Your Thyroid? Body composition and hormonal responses to a carbohydrate- restricted diet. Jul; 5. 1(7): 8. 64- 7. Dietary- induced alterations in thyroid hormone metabolism during overnutrition. Nov; 6. 4(5): 1. 33. Effect of low- carbohydrate diets high in either fat or protein on thyroid function, plasma insulin, glucose, and triglycerides in healthy young adults. Protein metabolism during weight reduction with very- low- energy diets: evaluation of the independent effects of protein and carbohydrate on protein sparing. Jul; 6. 2(1): 9. 3- 1. Protein sparing during treatment of obesity: ketogenic versus nonketogenic very low calorie diet. Apr; 4. 1(4): 4. 06- 1. Vegetable Oil and Weight Gain.
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