Does Espresso Inhibit Weight Loss?

"Does espresso inhibit weight loss?" is a question that's come up twice in today's emails, so I'll attempt to give a cogent answer. The short answer is, it depends. Espresso, at least the high-caffeine version, has a beneficial effect on dieters who drink regular coffee on a regular basis, and the opposite effect on dieters who drink decaf or don't drink coffee regularly.

First, it may be helpful to make a quick review of what espresso is. Espresso is a highly concentrated kind of coffee made by forcing very hot (but not boiling) water under high pressure through coffee that has been ground to a consistency between very fine and powder. Its effect on weight loss depends on whether it's drunk regularly, and there's a difference for dieters between regular and decaf.

An elaborate clinical trial at the University Hospital in Zurich (Switzerland) found that drinkers of regular coffee, whether dieting or not, experience much lower increases in blood pressure when exposed to stress. In the clinical trial, blood pressure in coffee drinkers went up to an average of 130/74 when they were exposed to emotional stress. Blood pressure in non-coffee drinkers went up to an average of 151/83 under the same conditions.

The significance of this finding for weight loss is that drinking regular coffee that contains caffeine seems to blunt the production of stress hormones--the hormones that also encourage the deposit of belly fat.

And since espresso has 3 times the caffeine of regular coffee, not only does drinking regular espresso not inhibit weight loss, it encourages it, but only in people who regularly drink coffee.

In people who don't regularly drink coffee, an espresso not only does nothing blunt hormonal reactions to stress, it may slightly increase blood pressure--which slightly increases insulin resistance and slightly increases the tendency to gain weight.

The Swiss study made on other interesting, unintentional finding.

Drinking too much water too fast has a paradoxical effect for dieters. If you drink more than about 2 cups (500 ml) of any water all at once, for the short time, you stimulate your sympathetic nervous system. When the water stretches the lining of your stomach and then your large intestine, your body releases hormones as if you had eaten a large amount of food.

In non-diabetics, both insulin (to store the sugars the gut is ready to get when it's stretched) and glucagon (to make sure the insulin doesn't lower blood sugars too much) enter the bloodstream. The problem is, insulin is much better at storing fat than it is at storing glucose, so drinking too much water, ironically, temporarily encourages storing fat. All you have to do to avoid this weight-gain enhancing effect is to avoid any kind of "sloshing" feeling after you drink water or any other fluids.

In diabetics, insulin production is delayed or reduced. The body still releases glucagon, however. This means diabetics can raise their blood sugars just by "stuffing" themselves, even with low- or no-calorie foods. Higher blood sugar leads to increased insulin resistance, increased insulin resistance leads to fat and weight gain. Again, however, the solution is as simple as avoiding too much food or drink at any one time. Always leave room for more.