breakfast: not lead to weight loss

breakfast: not lead to weight loss

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You forwarded this message on Mon 3/11/2019 6:28 AM

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Geoff A. Modest, M.D.

Mon 3/11/2019 6:27 AM

Geoff A. Modest, M.D.

A meta-analysis of randomized controlled trials found that skipping breakfast actually led to less total caloric intake and less weight gain (see wt loss breakfast not help bmj2019 in dropbox, or doi.org/10.1136/bmj.l42).

Details:

-- 13 RCTs were included from high income countries, mostly the US and the UK

    --one trial had 204 patients, all the rest were under 52 (and 7 had under 5 people)

-- all trials included measurements of body weight or energy intake

-- duration of intervention ranged from 2 to 16 weeks; mean follow-up: 7 weeks for weight, 2 weeks for energy intake

Results:

-- daily energy intake: participants assigned to breakfast consumed a total of 260 excess kilocalories per day (79-441 kcal)

    -- decreased daily energy intake was independent of whether the participants were habitual breakfast consumers or habitual breakfast skippers

    -- and, total daily energy intake was higher in groups consuming breakfast, regardless of whether they were habitual breakfast consumers or skippers

-- weight: participants who skip breakfast had a decrease of 0.44 kg (0.07- 0.82)

-- though these were small but significant differences, it should be noted that there was inconsistency across the trial results

-- and, these trials were considered to be of high risk of bias, especially since there was lack of blinding on outcome assessment. And the quality was low largely from the short-term follow-up

-- 4 trials assessed metabolic rates between the 2 groups, finding no difference

-- 5 of the studies also assessed physical activity, 3 showing no significant difference between breakfast consumers and skippers; 2 found that breakfast consumption was associated with increased physical activity during the morning. However total thermogenesis from daily physical activity was nonsignificantly higher in the breakfast consumers

Commentary:

-- there has been a long-held perception that eating breakfast was “the most important meal of the day”, and that skipping breakfast would lead to increased appetite and overeating later. Unfortunately, these conclusions were based on observational studies that have been shown to be quite biased: those not eating breakfast tended to have more unhealthy behaviors and be from lower social economic strata with the attendant associations (eg, less money to buy healthy foods, less access to stores that sell them, less access to arenas for physical activity....)

-- another concern was that those skipping breakfast would have lower metabolic rates, and therefore not burn off the calories, also not found in the study

    -- [i wonder if part of the issue is that breakfasts are often pretty terrible with lots of carbs, and the studies on high glycemic meals suggest that they lead to decreased metabolic rate, but low carb meals do not.  also, a high carb breakfast seems to lead to postprandial hyperinsulinemia leading to eating more: see http://gmodestmedblogs.blogspot.com/2018/09/high-glycemic-index-diet-causes-obesity.html ]

-- many international nutrition organizations strongly recommend breakfast. For example, the Academy of Nutrition and Dietetics from the United States in 2014 said “breakfast consumption is associated with a lower BMI and decreased obesity risk, while omitting breakfast is associated with a higher BMI and increased obesity risk”. Or the British Dietetic Association in 2016 said “skipping breakfast won’t help you lose weight. You could miss out on essential nutrients and you may end up snacking more throughout the day because you feel hungry”.  again, not sure that corn flakes is an essential nutrient...

-- some of these studies in the meta-analysis assessed hormone levels (leptin, ghrelin, glucagon, adiponectin, glucose, insulin, and the homeostatic model assessment of insulin resistance), generally not finding significant differences between the intervention groups

-- the studies focused on high income countries, thinking that there was more diversity of diets in resource limited settings. However, there certainly is a lot of dietary diversity in different areas and populations in the US...

-- given the inconsistency of the results along with concerns about risk of bias and the low quality of the studies, the researchers are cautious about over-interpreting the results. Also, these were really small studies!!

So, maybe breakfast is not the most important meal?? And, maybe yet again we’ve been making nutritional recommendations that are the opposite of what we should be doing (as with the fat restricted diets promoted for decades, which seem pretty clearly to be associated with increasing obesity)?? And these recommendations represent organizational biases (not backed up by reasonable studies) and incorrect assumptions/models of how the body works.... And, maybe a low glycemic index breakfast (eg oatmeal, or eggs) might have different results??

geoff​

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