Best Diet Confirmed by 5,248,916 Person-Year Study — Transcript

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1. 0:00A new study that tracked over 5 million
2. 0:02person-years of follow-up has confirmed
3. 0:03the best diet for your health, and this
4. 0:05is such a relief after all of the
5. 0:07flip-flops. So, we had the fat-free
6. 0:08craze in the '90s, then we had the
7. 0:10low-carb Atkins explosion in the early
8. 0:122000s. Now, there's keto influencers and
9. 0:14these high-protein cheese puffs on your
10. 0:16grocery shelves. There have been decades
11. 0:18of nutrition advice and billions in
12. 0:20revenue raked up by food industry who
13. 0:22are only too eager to cash in on these
14. 0:23trends, and people are still confused.
15. 0:26So, which diet is best when it comes to
16. 0:27your heart health? Should we aim for low
17. 0:29fat or should we target low carbs? And
18. 0:31is this whole debate just been a
19. 0:33distraction? So, the conversation around
20. 0:35diet and heart health began decades ago
21. 0:37in the 1950s. So, a dramatic shift was
22. 0:39happening, and suddenly everyone was
23. 0:41talking about heart disease. So, in
24. 0:43England, two Oxford researchers at the
25. 0:45time, they were carefully examining
26. 0:47official records and documented a
27. 0:48shocking increase in the numbers of
28. 0:50deaths from heart attacks and strokes.
29. 0:52They were killing adults in 1945 at a
30. 0:54rate of, and get this, 15 times greater
31. 0:57than in 1921. And the same pattern was
32. 1:00playing out in the US. So, deaths from
33. 1:02heart disease, they were quite rare in
34. 1:041900, and then they were the leading
35. 1:06cause of death by the mid-century. So,
36. 1:08there was an urgent need to understand
37. 1:09what exactly was going on. And one
38. 1:11theory that emerged identified diet as a
39. 1:14key culprit. Specifically, it suspected
40. 1:16that eating more saturated fat produced
41. 1:18higher LDL cholesterol levels in the
42. 1:20blood, and that higher LDL cholesterol
43. 1:22was an essential ingredient for plaque
44. 1:24accumulation within blood vessel walls.
45. 1:26So, a researcher by the name of Ancel
46. 1:28Keys put this theory on the map through
47. 1:30a groundbreaking research project. He
48. 1:32set out to find groups of people living
49. 1:34in different places who had very
50. 1:35different dietary patterns. So, in
51. 1:37particular, he was interested in how
52. 1:39much fat they ate. So, he ended up
53. 1:41assembling a massive data set of 16
54. 1:43cohorts of healthy men from select
55. 1:45populations across seven countries,
56. 1:47including several in Europe plus the US
57. 1:50and Japan. So, it was called the Seven
58. 1:52Countries Study, and the first findings
59. 1:54dropped in 1970. In that study, heart
60. 1:57disease was linked to blood cholesterol
61. 1:58levels, and those in turn were linked to
62. 2:00saturated fat in the diet. So, numerous
63. 2:03studies continued to examine the data
64. 2:05over the years as the cohorts aged, and
65. 2:07the relationship held. A 25-year
66. 2:09follow-up saw the same strong link
67. 2:11between saturated fat intake and heart
68. 2:13disease. So, Ancel Keys' research
69. 2:15pointed to saturated fat, not just any
70. 2:17fat, as the problematic element in the
71. 2:19diet. But the nuance was easily lost,
72. 2:22and guidelines often recommended
73. 2:24slashing total fat intake, so fat of any
74. 2:26kind. So, a statement, for example, from
75. 2:28the American Heart Association in 1986
76. 2:31pushed a reduction of saturated fat and
77. 2:34total fat, and it recommended that we
78. 2:36replace those fat calories with complex
79. 2:38carbs. And when the flawed food pyramid
80. 2:40in 1992 was released, it proclaimed the
81. 2:42same message. It guided consumers to
82. 2:44minimize all fats. It also graphically
83. 2:47represented refined carbs as the
84. 2:49foundation for a healthy diet, which is
85. 2:51wild. This picture dominated for decades
86. 2:53that the best way to beat heart disease
87. 2:55was to eat low fat. But in the
88. 2:57background, other researchers were
89. 2:59quietly exploring an alternative story.
90. 3:01So, at the same time that Ancel Keys was
91. 3:03launching his famed Seven Countries
92. 3:05Study, a British researcher by the name
93. 3:07of John Yudkin was pouring over the
94. 3:09statistics related to heart disease
95. 3:11deaths. So, just like Ancel Keys, he
96. 3:13spotted an interesting link between the
97. 3:15rate of heart disease and dietary
98. 3:17patterns. But the thing that jumped out
99. 3:19from the data that he was looking at
100. 3:20wasn't fat or even saturated fat. It was
101. 3:23sugar. So, Yudkin's focus on carbs
102. 3:25instead of fat as the driver of heart
103. 3:27disease, it didn't gain much traction at
104. 3:29the time. But in the late 1980s, a
105. 3:31landmark lecture began to change the
106. 3:33conversation. So, it was delivered by
107. 3:35Gerald Reaven, who was receiving the
108. 3:37prestigious Banting Award for diabetes
109. 3:39research. In that lecture, he argued
110. 3:41that insulin resistance was intimately
111. 3:43linked to heart disease and related
112. 3:45problems like high blood pressure. And
113. 3:46the driver of insulin resistance? Well,
114. 3:48in animal studies, it was a high-sugar
115. 3:51diet. So, by the year of 2000, more
116. 3:53important observational evidence was
117. 3:55starting to come in from human clinical
118. 3:56trials. So, a cohort of about 75,000
119. 3:59women had been followed up for 10 years,
120. 4:02and the researchers looked at the
121. 4:03relationship between heart disease and
122. 4:05glycemic load. Now, glycemic load is a
123. 4:08measure of how much food impacts blood
124. 4:10sugar levels. So, a high-impact glycemic
125. 4:12load, that raises blood sugar levels
126. 4:14more sharply. And at the top of the list
127. 4:16of the types of foods with a high
128. 4:18glycemic index are things like white
129. 4:20rice, white potatoes, white bread, and
130. 4:21sugary drinks. So, the results here were
131. 4:24stark. The diets with the highest
132. 4:25glycemic loads were associated with
133. 4:28double the risk of heart disease. And
134. 4:30this was even after taking into account
135. 4:32other common risk factors. And as this
136. 4:34research was happening in the
137. 4:35background, a cardiologist by the name
138. 4:37of Dr. Robert Atkins popularized a new
139. 4:39narrative inspired by it. His book, The
140. 4:42Diet Revolution, sold millions of
141. 4:44copies. It painted carbs as the enemy
142. 4:46when it came to heart disease and weight
143. 4:48loss, and it advocated for minimizing
144. 4:50them in the diet. But fat consumption?
145. 4:52Well, it was no problem according to
146. 4:53Atkins. So, we ended up with two
147. 4:55competing pictures. One says low fat is
148. 4:58the key to heart health, the other one
149. 5:00says it's low carb. And this debate
150. 5:02actually suited the food industry
151. 5:03nicely. So, they've been all too happy
152. 5:05to play along with these trends that
153. 5:07focus on specific macronutrients. When
154. 5:09low fat was the focus, they lined the
155. 5:11shelves with low fat products, and we
156. 5:13can see the same today with low carb.
157. 5:15And more recently, it's now the
158. 5:16high-protein craze. But this whole
159. 5:18approach is missing something profoundly
160. 5:20important, as we'll see in a moment.
161. 5:22Now, it seems like it should be an easy
162. 5:23matter to figure out which of these
163. 5:25positions is correct. But as the actual
164. 5:27data has come in, the picture has been
165. 5:28messy. The results have been mixed. So,
166. 5:31for example, one massive randomized
167. 5:33clinical trial that included nearly
168. 5:3550,000 participants with follow-up data
169. 5:37of 8 years, the researchers looked at
170. 5:39the impact of reducing total fat intake.
171. 5:42And that's important, they looked at
172. 5:43total fat intake, not just saturated
173. 5:45fat. The impact of reducing total intake
174. 5:48turned out to be extremely modest. Heart
175. 5:50disease risk did not budge, even though
176. 5:52there were some improvements in risk
177. 5:54factors. On the other hand, a different
178. 5:56trial put low fat and low carb diets
179. 5:59head to head. So, those on the low-carb
180. 6:01diet, they lost more weight over a
181. 6:026-month follow-up period, but there
182. 6:04didn't appear to be any advantage in
183. 6:06terms of heart disease risk metrics. All
184. 6:08of these mixed results has prevented any
185. 6:10clear winner from emerging, and the
186. 6:11debate has continued. And the food
187. 6:13industry has just cashed in on this
188. 6:15confusion. And all of this probably
189. 6:17shouldn't be a surprise, because there's
190. 6:18a serious problem that's often muddied
191. 6:20the waters when it comes to studies
192. 6:22investigating the linkages between these
193. 6:24diets and heart health. So, the problem
194. 6:27is this. Low fat and low carb, they're
195. 6:30just broad descriptions that can be
196. 6:31applied to many different kinds of
197. 6:33eating patterns. So, a low-fat diet, for
198. 6:35instance, that could mean a person is
199. 6:37anchoring their meals in things like
200. 6:39chickpeas and vegetables. A low-carb
201. 6:41meal, on the other hand, that could be
202. 6:42salmon, avocado, and spinach. Or, it
203. 6:45could be eggs fried in butter with a big
204. 6:47side of bacon. Now, of course, we would
205. 6:49expect to see profoundly different
206. 6:50health outcomes with these different
207. 6:52kinds of diets. It's not just the mix of
208. 6:54macronutrients that's important, it's
209. 6:56the quality of those macronutrients that
210. 6:58matters, too. And past studies on diet
211. 7:00and heart health, they've often not paid
212. 7:02careful attention enough to that
213. 7:04distinction. That's obviously critical.
214. 7:06And that brings us to the new study that
215. 7:08we're going to look at in this video,
216. 7:09because it was specifically crafted to
217. 7:11fill in this gap in the literature. The
218. 7:13study authors examined data from around
219. 7:15200,000 people from three separate
220. 7:17cohorts, and these cohorts were tracked
221. 7:19for a really long time, around 30 years
222. 7:22each. So, it is a ginormous data set.
223. 7:24And critically, they used food
224. 7:26questionnaires to distinguish diets not
225. 7:28only in terms of macronutrient quantity,
226. 7:30but also macronutrient quality. And they
227. 7:32divided the diet into healthy and
228. 7:34unhealthy versions of both low fat and
229. 7:37low carb diets. In the analysis, healthy
230. 7:39meat, for example, plant-based foods
231. 7:41versus animal products, or whole grains
232. 7:43versus refined grains. So, overall,
233. 7:45which dietary pattern won? Was it the
234. 7:47low fat or low carb? And we're going to
235. 7:49leave out the diet quality just for a
236. 7:51second here. So, the lowest carb diets,
237. 7:54they had a 5% elevated risk of heart
238. 7:56disease compared to those with the
239. 7:57highest carb intakes. Those with the
240. 8:00lowest fat diets had a 7% risk reduction
241. 8:03compared to the highest fat intakes. So,
242. 8:05low fat seems to be the number one
243. 8:07winner here, but the effects are
244. 8:08relatively modest. But all of that
245. 8:10changes when we look at diet quality.
246. 8:13The picture changes radically. So, those
247. 8:15who stuck to the healthy versions of the
248. 8:17low-carb diet had a 15% lower risk of
249. 8:20heart disease compared to those who were
250. 8:21furthest away from that eating pattern.
251. 8:24A high-quality low-fat diet also showed
252. 8:26nearly the same benefit, cutting the
253. 8:28risk by about 13%. And the unhealthy
254. 8:30versions of both diets raised risks to a
255. 8:33similar degree. And what's more, the
256. 8:35healthy versions of both diets, they
257. 8:37were linked to lower triglycerides, less
258. 8:39inflammation, and other markers of
259. 8:41better metabolic health. But before
260. 8:43looking about how all of this applies to
261. 8:44us, let me just mention some quick
262. 8:46caveats. So, first, this is an
263. 8:48observational study, so it isn't able to
264. 8:50tell us with much confidence about
265. 8:52causation. It also didn't look at more
266. 8:54extreme diets like a keto diet with
267. 8:56exceptionally low carb intake. And
268. 8:58finally, it doesn't mean that it never
269. 8:59makes sense to think about the
270. 9:00macronutrient intakes of our diet. It
271. 9:03just suggests that for most people, it's
272. 9:05unlikely to be the most helpful thing to
273. 9:07concentrate on. So, what's the big
274. 9:08lesson here? Well, we need to stop
275. 9:10focusing on low fat or low carb. The
276. 9:13macronutrient quantity doesn't appear to
277. 9:15be the key factor when it comes to heart
278. 9:17health. Instead, we have to focus on
279. 9:19food quality. We need to prioritize
280. 9:21plant-based proteins like chickpeas,
281. 9:23lentils, and beans over animal sources.
282. 9:26We want to prioritize whole foods over
283. 9:28processed, unsaturated fats over
284. 9:30saturated or trans fats. So, both low
285. 9:33carb and low fat dietary patterns, they
286. 9:35can work if we get the quality right.
287. 9:38And returning to fat for a moment,
288. 9:39there's one aspect of the study that's
289. 9:41likely to be quite controversial in the
290. 9:42comment sections of this video. So, the
291. 9:44fact that they placed animal-based food
292. 9:46sources in the unhealthy category. So,
293. 9:48this reflects a common understanding
294. 9:50that animal products, they're more a
295. 9:52problem for heart health because of the
296. 9:54saturated fat intake that they have, as
297. 9:56well as the lack of fiber, but you'll
298. 9:58find plenty of people online who claim
299. 9:59that this is just a myth. So, what is
300. 10:01the true story when it comes to
301. 10:03saturated fat and heart disease? Well,
302. 10:05make sure to check out this next video
303. 10:06here to find out what the latest data
304. 10:08tells us.