When eating carbs, do sugary drinks reduce calorie consumption compared to diet drinks?

Question

This recent report on Yahoo! Style claims that diet drinks may reduce the digestive system’s response to calorie intake leading to higher levels of snacking and higher calorie intake when diet drinks are taken with meals.

The argument runs like this (my emphasis):

We’ve all ordered fast food and thought it a good idea to offset the carbs with a diet drink.

It turns out that theory might not be right after all.

New research suggests that we might be better off ordering the full-fat version of our favourite drinks to guzzle down post-meal instead.

When diet drinks are consumed on their own, the artificial sweeteners - which are used as sugar replacements - have no impact.

When consumed alongside a carb heavy meal, the sweeteners act to decrease the brain’s response to sweet tastes.

That means we’re more likely to eat sweet treats to satisfy our cravings.

But the research was conducted on a small sample of people (45) and didn't study behaviour (just some brain responses, not what people actually consumed). And it seems to fly in the face of intuition: sweet drinks are full of empty calories, would any real effect be larger than their contribution to calorie consumption? So there are reasons to be skeptical.

So, is the claim that you should consume sugary drinks with carb-heavy meals to reduce your calorie consumption when compared to diet drinks credible?

Answer 1

Q: So, is the claim that you should consume sugary drinks with carb-heavy meals to reduce your calorie consumption when compared to diet drinks credible?

In the abstract of the study in Yahoo Style they said: "New research suggests that we might be better off ordering the full-fat version of our favourite drinks to guzzle down post-meal instead." Nobody in the original article in Cell Metabolism actually suggested that, but they just concluded:

• Consumption of sucralose combined with carbohydrates impairs insulin sensitivity.
• This metabolic impairment is associated with decreases in neural responses to sugar.
• However, sweet taste perception is unaltered.
• Insulin sensitivity is not altered by sucralose or carbohydrate consumption alone.

The pretty much only observation in this study was that drinking beverages with the combination of a carbohydrate (maltodextrin) and an artificial sweetener (sucralose) for 10 days decreased insulin sensitivity (which resulted in higher blood glucose levels after meals). They didn't even check for calorie intake or body weight changes.

In randomized controlled trials, low-energy sweeteners (LES) did not increase energy intake (EI) or body weight (BW): Does low-energy sweetener consumption affect energy intake and body weight? A systematic review, including meta-analyses, of the evidence from human and animal studies (International Journal of Obesity, 2016):

The preponderance of evidence from all human randomized controlled trials indicates that LES do not increase EI or BW, whether compared with caloric or non-caloric (for example, water) control conditions.

In a San Antonio Heart Study from 1979 to 1988, in 5,158 adults: Fueling the Obesity Epidemic? Artificially Sweetened Beverage Use and Long‐term Weight Gain (Obesity, 2012), they have observed an association between artificially sweetened beverages and weight gain. The researchers suggested that the results were probably due to reverse causality: It is possible that overweight people drink diet soda with artificial sweeteners [ASs] to prevent additional weight gain (but they continue to gain weight), rather than drinking diet soda makes them fat:

Individuals seeking to lose weight often switch to ASs in order to reduce their caloric intake. AS use might therefore simply be a marker for individuals already on weight‐gain trajectories, which continued despite their switching to ASs.

In summary, there seem to be no studies that would check for an association between a combined effect of high-carb meals and diet drinks on overall calorie intake, so there is no convincing reason to suggest sugary drinks instead.