Once Again Confirmed – Diet is What’s Going to Make You Burn Calories, Not Exercise

Take a look at this article by Vox, published in the beginning of 2019 – it explains the simple (but often forgotten) science behind how much more diet matters than exercise, when it comes to burning calories. Here’s also a much more in-depth piece (by the same author), based on more than 60 published scientific studies.

The conclusion is clear – physical exercise accounts for a relatively insignificant amount of the calories you burn daily. Or, as I’ve been saying for years – it would take you up to an hour of brisk walking to burn off the energy in a serving of ice-cream.

Here are the most important points from the article:

  • You cannot outrun a bad diet
  • after a certain amount of exercise, you don’t keep burning calories at the same rate: Total energy expenditure may eventually plateau
  • Exercise is excellent for health, but it’s not important for weight loss. The two things should never be given equal weight in the obesity debate
  • “Pretend you didn’t exercise at all,” – “You will most likely compensate anyway, so think of exercising just for health improvement but not for weight loss.”

Keep in mind – this only applies to the caloric model of weight-loss and doesn’t take hormones into account

Of course, there is much more to health and weight loss than calories. The caloric model clearly doesn’t explain why some people(particularly the young ones) can stay thin even when eating in a caloric excess. There are many other factors, like leptin sensitivity, insulin secretion, diurnal variation of cortisol, water weight storage due to ADH reductions and many, many more. If you like to read more on those topics, take a look at my other articles, concerning those topics.

Artificial Sweeteners – Are They Hindering Your Fat Loss Progress, By How Much and How?

Using drinks containing artificial sweeteners seem like a practical way to satisfy your cravings for sweets, without the calories. However, there has been some controversy as to how those chemical affect your endocrine system. Even as far back as 1987, it was clear that Acesulfame K dramatically increases insulin secretion – as much as plain glucose!

The basic mechanism behind this detrimental effect? The sweet taste of the sweeteners makes your body react as if you are ingesting glucose. So, it prepares for the coming wave of high blood sugar, by secreting insulin. Insulin of course, is the main anabolic hormone, responsible for storing fat, although that seems to be the case mainly with high-fat meals.

A more thorough study done in 2010, concluded that consuming deserts, sweetened with artificial sweeteners are actually an effective way to reduce calories – when people were instructed to eat as much food as they wanted, the group that ate the artificially sweetened deserts, clearly consumed less total calories.

“The key finding was that participants did not compensate by eating more at either their lunch or dinner meal when they consumed lower calorie preloads containing stevia or aspartame compared to when they consumed higher calorie preloads containing sugar. ”

When comparing the three main sweeteners – stevia and aspartame, stevia was clearly the healthier option – participants in the stevia group had lower insulin levels 20 minutes after the test meal, compared to both the sugar AND the aspartame-containing meal.

Long-term effects of artificial sweeteners – this is where it can get potentially bad

So, when looking at short-tem effects, artificial sweeteners increase insulin secretion(which is bad), but seem to satisfy your sweet tooth and extinguish cravings for sweets, at least partially. However, when we look deeper, things of course get more and more complex.

A 2014 study on aspartame, sucralose and saccharin found something quite interesting – if you consume artificial sweeteners often, your body ‘learns’ that it doesn’t have to boost your metabolism after you eat. Which is bad and can potentially lead to very bad effects when it comes to fat metabolism. In particular, thermo-genesis was reduced – a clear sign, that you are burning less calories. Here’s the conclusion of the study:

” Recent data from humans and rodent models have provided little support for ASB(artificially sweetened beverages ) in promoting weight loss or preventing negative health outcomes such as T2D(type 2 diabetes), metabolic syndrome, and cardiovascular events. Instead, a number of studies suggest people who regularly consume ASB are at increased risk compared with those that do not consume ASB; with the magnitude of the increased risks similar to those associated with SSB(sugar-sweetened beverages )”

In conclusion:

Consuming artificial sweeteners instead of sugar will reduce your caloric consumption, without making you hungrier. The bad metabolic effects of artificial sweeteners are not completely clear, especially when compared to those of plain sugar.

Consuming less than the following amounts of sweetners is highly unlikely to cause you any health issues whatsoever:

Aspartame (ADI = 50 mg/kg/day or 21 cans of diet soda for a 160 pound person)

Sucralose (ADI = 5 mg/kg/day or 31 splenda packets)

Acesulfame Potassium (ADI = 15 mg/kg/day or 30 cans of diet soda)

Saccharin (ADI = 5 mg/kg/day or 10 sweetener packets)

Stevia (ADI = 4 mg/kg/day or 40 stevia packets)