The second-meal phenomenon is associated with enhanced muscle glycogen storage in humans

Abstract

The rise in blood glucose after lunch is less if breakfast has been eaten. The metabolic basis of this second-meal phenomenon remains uncertain. We hypothesized that storage of ingested glucose as glycogen could be responsible during the post-meal suppression of plasma NEFAs (non-esterified fatty acids; 'free' fatty acids). In the present study we determined the metabolic basis of the second-meal phenomenon. Healthy subjects were studied on two separate days, with breakfast and without breakfast in a random order. We studied metabolic changes after a standardized test lunch labelled with 3 g of 13C-labelled (99%) glucose. Changes in post-prandial muscle glycogen storage were measured using 13C magnetic resonance spectroscopy. The rise in plasma glucose after lunch was significantly less if breakfast had been taken (0.9+/-0.3 compared with 3.2+/-0.3 mmol/l, with and without breakfast respectively; P<0.001), despite comparable insulin responses. Pre-lunch NEFAs were suppressed after breakfast (0.13+/-0.03 compared with 0.51+/-0.04 mmol/l) and levels correlated positively with the maximum glucose rise after lunch (r=0.62, P=0.001). The increase in muscle glycogen signal was greater 5 h after lunch on the breakfast day (103+/-21 compared with 48+/-12 units; P<0.007) and correlated negatively with plasma NEFA concentrations before lunch (r=-0.48, P<0.05). The second-meal effect is associated with priming of muscle glycogen synthesis consequent upon sustained suppression of plasma NEFA concentrations.

Fasting Until Noon Triggers Increased Postprandial Hyperglycemia and Impaired Insulin Response After Lunch and Dinner in Individuals With Type 2 Diabetes: A Randomized Clinical Trial

“…The prolonged elevation of plasma FFA levels triggered by the extension of the overnight fast on the NoB day correlated with reduced early insulin release, higher glucose, and less suppressed glucagon and FFA levels after lunch and dinner. A similar positive correlation was observed between FFA and glucose levels after lunch in people with and without diabetes when breakfast was omitted (17)(18)(19). Acute elevation of FFA by intravenous infusion or omission of breakfast has been reported to cause inhibition of insulin-stimulated muscular glucose transport.…”

“…Although omission of breakfast has been demonstrated to be associated with a higher glycemic response after a liquid preload (16) or lunch in healthy individuals (17) and in individuals with type 2 diabetes (10,18,19), postprandial glycemia after other meals ingested later during the day has never been assessed. A recent study showed that breakfast skipping resulted in a higher postprandial glycemic response after lunch and dinner in healthy individuals (20).…”

The effect of breakfast on appetite regulation, energy balance and exercise performance

“…Additionally, breakfast omission caused an increase in glucose and insulin response to the liquid meal, compared with breakfast consumption. This dampened glycaemic response to the second meal of the day, is known as the 'second meal effect' which may be related to glycogen storage (34) . Gonzalez et al (25) similarly found a tendency for an increased glucose and insulin response to a 1500 kJ liquid meal consumed 3 h after omission, compared with consumption of breakfast, although active GLP-1 concentrations were not different between trials.…”

The Second Meal Effect and Its Influence on Glycemia

“…Research on the second meal effect has recently become more popular due to the fact that poor glycemic control is linked to multiple health complications [19]. In 1988, Wolever et al [15] studied the impact of meals with differing GIs on the second meal effect.…”

“…Jovanovic et al [19] studied the postprandial glycemic and insulemic responses to a standard lunch meal on two separate occasions; with and without breakfast being consumed that same day. Glycogen was measured using 13 C magnetic resonance spectroscopy before lunch.…”