Sept. 3, 2009 — Excessive late-night eating has long had a bad reputation, with studies showing it leads to weight gain.

Now, in a new study, researchers from Northwestern University have found that eating at the “wrong” time leads to more than twice as much weight gain, even when the overall calories consumed are the same as those eaten at appropriate times.

The study was conducted on mice separated into two groups (those who would normally eat at night and those who would normally eat during the day). The study showed rats who ate at the “wrong” times (day feeders who ate at night) gained almost twice as much weight as the other rats eating the same amount of food during the normal eating times.

Obesity and weight gain often go hand-in-hand with pre-diabetes and type 2 diabetes. Although studies have not been done on humans, it makes sense that late night eating could also lead to abnormal weight gain in humans, too.

Source: Eat Late, Put on Weight? Study Shows Eating at the ‘Wrong’ Time of Day Could Lead to Weight Gain. By Kathleen Doheny WebMD Health New.

In a 2002 study published in Diabetes Care, a team of physicians from the Netherlands announced their findings: that caffeine decreased healthy test subjects’ insulin sensitivity by 15%.

In another study reported by MedicineNet.com, people with diabetes were given caffeine pills equivalent to two cups of coffee.  The caffeine alone caused their blood sugar to rise by 8% and was reported higher after every single meal.  This was not true for the control group who did not take caffeine.

According to Suite101.com:

Patients struggling to lose weight and control blood sugar due to a diagnosis of insulin resistance or pre-diabetes should decrease or eliminate dietary caffeine.

That was back in the 1980s.  Today, we know more about what causes insulin resistance and pre-diabetes and how to treat it. We also know that anytime you eat carbohydrates your body needs to produce insulin to move glucose from the bloodstream into body tissues and cells.

People who are insulin resistant need to make more insulin than normal to maintain normal blood sugars (and, in some cases, even then they cannot maintain normal blood sugar and end up pre-diabetic or develop type 2 diabetes).

All this extra insulin does some really bad stuff to you, your body, and your weight:

• Over time, it can wear out your pancreas
• Excess insulin interferes with other hormones, like estrogen and can lead to irregular periods and infertility;
• High blood pressure;
• Heart disease;
• Increased risk of developing pre-diabetes, type 2 diabetes, and gestational diabetes during pregnancy.

Does this look familiar? The darkening shown here is acanthosis nigricans caused by insulin resistance and a diet too high in carbohydrates.

Overproduction of insulin (hyperinsulinemia) also causes other problems, including:

• Scalp hair loss (especially in women)
• Hirsutism
• Skin tags
• Acanthosis nigricans
• Adult acne

The bottom line is this:  the more carbohydrates you eat, the more insulin you produce.  The more insulin you produce, the harder it becomes to lose weight.  Not only is insulin a hormone that triggers the body to store fat, excess insulin cannot be excreted and is then stored as body fat.

Before you grab the side of fries, late-night ice cream snack, or other high-carb, no-nutrient foods, remember, if you have pre-diabetes or insulin resistance, your body simply will not properly metabolize these foods and you will make your condition worse.

In the two well-controlled studies that included a lifestyle intervention arm, substantial efforts were necessary to achieve only modest changes in weight and exercise, but those changes were sufficient to achieve an important reduction in the incidence of diabetes. In the Finnish study, weight loss averaged 9.2 lb at 1 year, 7.7 lb after 2 years, and 4.6 lb after 5 years (31,53); the exercise component of the intervention called for “moderate exercise” of 30 min/day. In the DPP (33), the lifestyle group lost ∼12 lb at 2 years and 9 lb at 3 years (mean weight loss for the study duration was about 12 lb or 6% of initial body weight). In both of these studies, most of the participants were obese (BMI >30 kg/m2).

Read the full report: Prevention or Delay of Type 2 Diabetes